What will determine the percentage referral fee that you will be charged by Amazon when your product sells?

The product category is the primary factor determining the percentage referral fee Amazon charges. Amazon has different referral fee percentages for various product categories (e.g., electronics, clothing, books), which are outlined in their fee schedules. While product price influences the absolute dollar amount of the fee, it doesn't change the percentage. The quantity sold and product size might affect other fees (like fulfillment or storage fees), but not the percentage referral fee itself.