ETDA has issued a DPS guideline requiring e-marketplaces to disclose a Total Take Rate (TTR): all fees, including payment, infrastructure, campaign, coupon, ad and affiliate costs, as a percentage and in baht. Platforms should show the baseline and the extra cost of joining a campaign before you confirm. Example: a 1,000-baht item with a 100-baht seller-borne discount and 12.96% base fees gives 116.63 baht baseline; a 108-baht campaign cost raises TTR to 24.96%. Platforms must give 30 days' notice of fee changes. Before joining a promotion, compare your net receipt with and without it, and ask for the TTR calculator.