Both numbers you read exist in the market, and they're paying for different things. The flat fee, commonly somewhere in the several hundred to a couple thousand range, is what an investor pays for a lead they still have to work. The percentage arrangement shows up when a bird dog is feeding someone repeatedly and the investor wants the incentive tied to the size of the outcome. Neither is standard. Fees get negotiated per relationship, and both get paid on closing, not on delivery.
Your repair knowledge is worth real money, and here's why. Most leads an investor gets are an address and a guess. When you can say the roof is failing at the valleys, the foundation looks fine, and the kitchen is a gut, you've removed a site visit and a contractor call from their week. Investors notice which sources save them time and they call those sources first.
Be careful about one thing: giving a repair number is fine as your read on the work. Presenting it as a formal estimate or a bid, when you're also collecting a finder's fee on the same house, can muddy what role you're in. Keep the two separate in writing.
Also worth knowing before you send anything. Get the fee agreement in writing with your first investor, plain language, one page, covering what a qualified lead is and when payment happens. Most disputes in this space are about whether a lead was already known to the investor.
