i have 93 transam, i wanted to know where i can buy the cheapest optispark and how much will it cost? i guess mine is the NON-VENTED?

 

Yes yours is non vented, best bet is Dal or Jason Cromer, do a search and you'll find there info there. Now would be a good time to do a vented conversion. The non vented costs a bit more, and for not very much more money you could have a vented one which won't die as easy.