An assignment fee is what a wholesaler earns for passing a purchase contract to another buyer. The wholesaler agrees on a price with the seller, then assigns the right to buy at that price to an investor. The investor pays the fee on top, usually at closing. There is no standard amount.
Assignment fee = price the end buyer pays minus contract price with the seller
Say a house will be worth $250,000 fixed up and needs $25,000 of repairs. An investor using the 70% rule will pay at most $250,000 × 70% = $175,000, minus $25,000 of repairs, or $150,000 with the fee included. A wholesaler who has the house under contract for $140,000 can assign that contract for a $10,000 fee, because $140,000 + $10,000 = $150,000. At a contract price of $145,000, only $5,000 of room is left.
If you are the buyer, treat the fee as part of your purchase price. A $140,000 contract with a $10,000 fee is a $150,000 purchase, and it has to fit under your maximum allowable offer.
The fee commonly appears on the settlement statement, so the seller may see it. Rules on wholesaling vary by state. Some states require a license or specific disclosures, and some contracts cannot be assigned at all, so check the rules where you operate.