The fee structure difference centers on whether you pay per item sold or pay a fixed monthly subscription rate. An Individual account charges ninety nine cents for every item sold plus standard referral fees, which suits people selling fewer than forty items a month. A Professional account charges a flat thirty nine dollars and ninety nine cents monthly subscription fee regardless of how many units you sell. If you sell more than forty products every month, the Professional plan is more economical because it waives the per item fee entirely.