Referral fee in internet marketing refers to an arrangement when a referrer is compensated based on volume of sales or number of conversions. Referral fee can be flat, in other words a set amount that is paid per customer or the size of the fee can be linked to the volume of sale(s). Referral fees can be paid out one time, or they can be paid on an on-going basis. For example it is common for referral fee to be of recurring nature when the client referred is charged a recurring membership fee and vice versa.