Suggested bid and bid range

Amazon shows a suggested bid beside a keyword, ad group or campaign, together with a low-to-high range — its own worked example is $0.70 with a $0.40–$1.40 range. You see it at campaign creation and afterwards on the Targeting tab in campaign manager. Both figures, the help page says, are calculated from bids for ads similar to yours that won impressions over the past 7 days, and are updated daily as competing bids and ads move. The unit follows the objective rather than the product line: CPC for Sponsored Products, for Sponsored Brands "drive page visits" and for Display's page-visits and conversions objectives; vCPM for Sponsored Brands "grow brand impression share" and for Display's vCPM inventory. Display is not vCPM-only — check the objective before you read the number.

Read the sample carefully: winners only. Losing bids never enter it, so the range prices admission among advertisers who already paid, and what Amazon promises for paying it is competitiveness — bid at or above the range and "your ads will be more competitive in auctions". Nothing there is denominated in your margin. The figure carries no sample size and no confidence interval, so a wide range on a thin keyword and a dense one look identical. Compute break-even CPC from price × contribution margin × conversion rate first, then use the range only as a feasibility check. Amazon says a bid below the suggested bid can still win impressions — a break-even under the low end makes volume thin, a reason to demote the keyword to harvest, not to bid up.