Walmart Marketplace charges a referral fee that ranges from 6% to 20% depending on category, with most categories sitting at 15% (Walmart Marketplace Learn — Referral fee schedule for contract categories). There's no per-item minimum fee the way some marketplaces charge, and Walmart doesn't take a monthly or setup fee at all — the referral fee is the whole story for a self-fulfilled seller (Walmart Marketplace — Pricing).
The detail sellers miss is what happens within a category's rate structure. Walmart's published schedule assigns a single referral fee percentage per category — but that percentage is what applies to the full sale price once you're in that category, and category assignment interacts with price in ways that are easy to get wrong when you're setting a price a few dollars above or below a round number. If a category's fee percentage differs from a neighboring category or from a different price band Walmart treats separately within its schedule, moving your price by even $0.50 can change which line of the schedule your listing falls under — and because the fee applies to the entire sale price, not just the amount above the boundary, crossing that line can cost you more than the price increase actually earned you.
This is a structural fact about how bracket-based fee schedules work, not a Walmart-specific quirk — the same hard-floor mechanic shows up in TikTok Shop's Collectibles fee cliff at $10,000, where crossing the threshold changes the entire fee calculation rather than just the marginal dollar. Walmart's schedule is denominated in category assignments and percentage-per-category rather than a single dollar cliff, but the underlying trap is identical: sellers price by round numbers or by what the market will bear, without checking whether that price change also flips which fee percentage applies to the whole transaction.
Why category assignment is the real bracket, not the price
Walmart's referral fee schedule doesn't publish a single