Without people (vendors) selling things flea markets don't exist. Without customers there's no need for vendors. The vendor/customer relationship is what a flea market is all about. It's a great relationship and it can/should be win/win. On the vendor side, the idea is for the vendor to make enough to reimburse herself/himself for his/her expenses: the amount the vendor has in a piece, the amount of the vendor's travel costs, the amount of the hostess/host's space fees, etc. The idea is for the vendor to earn enough in sales so the day was valuable financially as well as socially (vendors tend to be fun people).