Sponsored Products: Campaign Structure, Ad Groups, and Product Targeting
Three levels, three jobs
A Sponsored Products campaign holds the budget, bidding strategy, start and end dates, placement multipliers and campaign-level negatives. Inside it, each ad group holds the advertised ASINs, the keywords or product targets, and the bids attached to them. Nothing inherits downward: there is no ad-group budget, and there is no campaign-level keyword bid.
Manual versus automatic
Automatic campaigns let Amazon match your products to customer search terms and to products. Manual campaigns let you choose keywords, ASIN targets (defensive or conquesting), or category targets narrowed by refinements such as brand, price, rating and Prime status. A common architecture keeps one automatic campaign per product group as a discovery engine and mirrors converting search terms into manual exact-match ad groups.
Product targeting specifics
Product targeting can point at individual ASINs, at whole categories, or at categories narrowed by refinements. It is the right tool for competitor detail pages, cross-sells and defensive placements on your own listings. Use negative product targets to keep ads off unprofitable ASINs and negative keywords to filter irrelevant queries.
Traps
Questions love to blur the levels: budget at campaign level, bid at keyword or target level with an ad-group default, negatives available at both levels. Another common error is mixing unrelated ASINs in one ad group, which makes bid and negative decisions unreadable, or editing a keyword bid and expecting the budget to change.
Rule of thumb
One theme per ad group - a tight cluster of one to five substitutable ASINs and one match-type family - so any performance change has a single plausible cause.