newbie ?, How much BMV should I sell prop. to a rehabber?

Pleas help me with my newbie question? What % below fair market value should I sell a property to a rehabber? And at what % below fair market value should I purchase a property?
I know profit varies, is there a minimum profit before I say it is not a good buy? Thanks. Jacque1

In my area investors typically want 30% under ARV (or ~30k if you get into more expensive property) - cost of repairs - cost of purchase.

Thanks, MBentley. By the way what area are you in? How can I figure what % the investors in my area want? Is it that a group of investors want a certain %? And would that same % be the same for the same county those investors live in. For example, if I find that investors in Brea want 30% below ARV would other investors in Pomona want 30%? Or do I need to ask every investor what they are looking for? Jacque1