>>6208432Optimus and Soundwave already have masterpieces out that are spot on for their G1 looks. But if you really need one for Optimus, look up Toy World Primorion. Arcee has one coming up from Toy World called Leah, but I don't think it's anytime soon.
For more g1 stuff, look up Fanstoys, toy world, DX9 and Maketoys.
Price wise, it's hard to say, usually 3rd party is more expensive but the masterpiece-like figures are pretty competitive to their official counterparts.