Advertising on Online Marketplaces

Why Marketplace Advertising Is Different from Google and Social Ads

Marketplace ads reach buyers with the highest possible purchase intent. Someone searching on Amazon has already decided to buy something, they are choosing which product to buy. Someone searching on Google might be researching, comparing, or just browsing, and converting that general interest into a purchase requires multiple steps. This high-intent audience is why marketplace advertising typically delivers higher conversion rates (8 to 15 percent on Amazon PPC) compared to Google Ads (1 to 3 percent for ecommerce) or social media advertising (1 to 2 percent).

The trade-off is that marketplace ads only reach buyers on that specific marketplace. Google Ads and social media ads build awareness and drive traffic to your own website, building your brand beyond any single platform. Marketplace ads keep buyers inside the marketplace ecosystem, generating sales that accrue platform fees and build your marketplace seller ranking but do not build an independent customer relationship. Both types of advertising serve different strategic goals: marketplace ads maximize sales on the platform, while external ads build brand independence and drive traffic to your own online store.

Amazon Sponsored Products

Amazon's Sponsored Products is the largest marketplace advertising platform, generating over $45 billion annually in ad revenue. Sponsored Products are pay-per-click (PPC) keyword-targeted ads that appear in search results and on product detail pages, looking nearly identical to organic results except for a small "Sponsored" label. When a buyer clicks your ad, you pay your bid amount, and the buyer lands on your product listing. You only pay for clicks, not impressions.

Campaign types include Automatic campaigns, where Amazon selects keywords based on your listing content and shows your ad for relevant searches, and Manual campaigns, where you choose specific keywords and set bids for each. Start with an Automatic campaign for two to four weeks to discover which keywords generate clicks and conversions, then transfer the best-performing keywords to a Manual campaign with optimized bids. Set your daily budget at $20 to $50 for a single product launch and adjust based on performance data.

The key metric is Advertising Cost of Sale (ACoS), which measures what percentage of your advertising-generated revenue was spent on ads. An ACoS of 25 percent means you spent $25 in ads to generate $100 in sales. Your target ACoS depends on your profit margin: if your pre-advertising profit margin is 35 percent, any ACoS below 35 percent generates net profit from advertising. Most sellers target an ACoS of 15 to 25 percent for ongoing campaigns and accept a higher ACoS of 30 to 50 percent during product launches when the goal is generating sales velocity and reviews rather than immediate profit.

Amazon also offers Sponsored Brands (banner ads featuring your brand logo and multiple products, available only to Brand Registry sellers) and Sponsored Display (retargeting ads that follow shoppers who viewed your product across Amazon and partner websites). These formats serve brand awareness and customer retention goals but require larger budgets and more sophisticated management than Sponsored Products.

eBay Promoted Listings

eBay's Promoted Listings come in two formats: Standard (pay-per-sale) and Advanced (pay-per-click). Promoted Listings Standard is the more popular option because you only pay when your promoted listing results in a completed sale, eliminating the risk of paying for clicks that do not convert. You set an ad rate (typically 2 to 10 percent of the final sale price) and eBay boosts your listing's visibility in search results and related items sections. If a buyer clicks your promoted listing and purchases within 30 days, you pay the ad rate on top of your regular final value fees.

The strategy for Promoted Listings Standard is setting the minimum effective ad rate for each listing. eBay suggests ad rates based on your category and competition, but these suggestions tend to be higher than necessary. Start at the minimum suggested rate (usually 2 to 3 percent) and increase by 1 percent increments every two weeks until you see meaningful traffic increases. Many sellers find that 3 to 5 percent ad rates deliver 80 percent of the benefit of higher rates, with diminishing returns above 5 percent. Promote your highest-margin items first, since the ad fee comes directly out of your margin, and items with thin margins become unprofitable when you add a 5 percent promotion cost on top of the 13.25 percent final value fee.

Promoted Listings Advanced uses a pay-per-click model similar to Amazon PPC, with keyword targeting and bid-based pricing. You set bids for specific keywords, and eBay charges you per click regardless of whether the buyer purchases. Advanced is better suited for sellers with higher-margin products and enough sales data to optimize keyword bids based on conversion rates. The minimum daily budget is $1, but most sellers need $5 to $20 per day per campaign to generate enough data for meaningful optimization.

Walmart Sponsored Products

Walmart's advertising platform, Walmart Connect, offers Sponsored Products that appear in search results and browse pages on walmart.com. The system uses a keyword-based PPC model similar to Amazon's, with automatic and manual campaign types. Average cost per click on Walmart ranges from $0.30 to $1.50, significantly lower than Amazon's $0.50 to $5.00+ per click in most categories, because fewer sellers are competing for ad placements on Walmart compared to Amazon's saturated advertising market.

The lower competition on Walmart's ad platform represents an opportunity for sellers who are already selling on Walmart Marketplace. The same product keyword that costs $2.00 per click on Amazon might cost $0.50 per click on Walmart, delivering comparable conversion rates at a fraction of the advertising cost. Walmart requires a minimum daily budget of $1 per campaign and recommends starting with $20 to $50 per day for new campaigns. Track Return on Ad Spend (ROAS) as your primary performance metric: a ROAS of 4x means every $1 in ad spend generates $4 in revenue, which is profitable for most product margins.

Walmart also offers Sponsored Brands (banner ads at the top of search results) and Display Ads (banner ads across walmart.com). These formats require higher budgets ($100+ per day) and serve brand awareness goals rather than direct response. For most marketplace sellers, Sponsored Products is the only Walmart ad format that delivers consistent ROI at manageable budget levels.

Etsy Ads

Etsy Ads combines on-site advertising (promoted listings in Etsy search results) with Offsite Ads (promoting your products on Google, Facebook, Instagram, and Pinterest). On-site Etsy Ads use a daily budget model where you set a maximum daily spend (minimum $1 per day) and Etsy automatically distributes your budget across your promoted listings based on predicted performance. You pay per click, with typical costs of $0.20 to $2.00 depending on your product category and competition.

Etsy's Offsite Ads program is separate and somewhat controversial among sellers. Etsy automatically enrolls all sellers in Offsite Ads, which promotes your listings on external platforms. When a sale results from an offsite ad click (within 30 days), Etsy charges a 15 percent fee on the sale (12 percent for sellers earning over $10,000 annually). This fee is on top of Etsy's standard listing, transaction, and processing fees, potentially bringing total fees on an offsite-ad-generated sale to 25 to 30 percent. Sellers earning under $10,000 annually on Etsy can opt out of Offsite Ads, while those earning above that threshold cannot opt out.

For on-site Etsy Ads, start with a $5 per day budget and let campaigns run for at least two weeks before evaluating performance. Etsy's advertising dashboard shows impressions, clicks, orders, and revenue attributed to ads, along with your cost per click and ROAS. Profitable Etsy Ad campaigns typically achieve a ROAS of 3x to 5x, meaning $15 to $25 in revenue per $5 spent. If your ROAS is below 2x after two weeks, either your listing needs optimization (better photos, title, pricing) or the product category is too competitive for profitable advertising on Etsy.

Budget Planning Across Platforms

New sellers should allocate 10 to 15 percent of their expected monthly revenue to advertising during the first three to six months on any marketplace, then adjust based on actual performance data. For a seller expecting $5,000 per month in marketplace revenue, that means a starting advertising budget of $500 to $750 per month. Distribute this budget across platforms proportional to each platform's revenue contribution: if Amazon generates 60 percent of your sales and eBay generates 40 percent, allocate roughly 60 percent of your ad budget to Amazon and 40 percent to eBay.

The critical discipline is measuring return on every advertising dollar and cutting campaigns that do not deliver profitable results. An Amazon campaign with a 50 percent ACoS for three months is not "building brand awareness," it is burning money. A Promoted Listings campaign on eBay at 8 percent ad rate that does not measurably increase sales velocity versus the same listing without promotion is wasted spend. Review campaign performance weekly, pause underperformers, and reallocate budget to the campaigns and platforms that generate the strongest returns. The conversion optimization guide covers how to improve your listing conversion rate, which directly improves advertising ROI by generating more sales from the same number of clicks.