I have bought many cars with blown head gaskets including some jeeps, and I never pay more than $1,000 to $1,500 for them. If its an inline 6 with an easy head gasket job and it has a GREAT body and interior, you MIGHT be able to get like $1000. But if its a V 6 or 8 and the body and interior aren't that great with that high of mileage, I doubt you'll get anything over 4 or 5 hundred. To get it fixed will run between $600 - $1000 depending on if its a V or an inline, and whether the head is cracked or warped or theres some valve/piston damage.