If you siezed it and it won't turn over anymore, the piston is dead. The cylinder probably needs replating.
the best thing you can do to save money is to take the cylinder off yourself, then take it into a shop. I'm not sure how you would go about this if the piston is melted (a.k.a. welded) onto the cylinder, which can happen. I'm sure you could find a website on how to do this somewhere. I personally would stuff some rags into the crankcase to keep chunks out (assuming you can get the cylinder up far enough to do so), then use a dead-blow hammer to tap the cylinder off (any metal hammer will ruin the cylinder, if it's stuck tight I doubt you could get enough force with a rubber hammer. Dead-blow hammer is the way to go)
Once you have the cylinder off, you could take that into the shop, and they might examine it for free and let you know what your options are (no guarantees on this one, I've never had to take anything in to a shop since my stepdad is a mechanic)