What % of the Market Value do you offer to motivated sellers to make a deal?

[Darvin Ezell]

Ok say for example, the marketing that I have done has paid off and I generate some leads and get some calls coming in. I get a motivated seller that needs to sell their house and wants my help. How do I know what amount to offer them for their property? Is there a certain percentage of the Market Value that I offer them so i dont make my offer toooo low?