1997 Mitsubishi Eclipse blown head gasket

I am looking at buying a 1997 eclipse for really cheap because it has a blown head gasket, I was wondering if it was a good idea, and how much it would cost to replace a head gasket on one of these cars. I also looked online and saw there was a Thermagasket Head & Block Treatment Kit. it said it seals the gasket but I'm kinda wary on these quick fix things. are these worth trying or is it better to just pay for the repairs. thankyou for your time.
[img:170f624576]http://www.2carpros.com/forum/automotive_pictures/164598_0104020103030116002008030249bc860b3d23c010560009eb_1.jpg[/img:170f624576]