You are correct, however, consider that the quality of the work will probably be much higher from someone who is willing to do this kind of unorthodox pricing.

You are correct, however, consider that the quality of the work will probably be much higher from someone who is willing to do this kind of unorthodox pricing. One reason is because if any issues or changes come up then they'll be fine with adjusting their work without changing the price. You'll probably wind up paying less overall. It even seems reasonable to spend 10 minutes figuring out what a fair price is, then pay them 20% less, since what you think is fair is usually too high. And if it isn't, oh well... it was their risk doing this pricing model in the first place. This pricing model relies on high quality of the finished product. It wouldn't work otherwise. Therefore I don't understand why you'd walk away. You really would, if this were offered to you? It's likely you'd get an extremely good quality finished product along with any changes you needed afterwards.