adding keyless entry

Can I get a used module (receiver) & buy a remote and get it to work? or get a aftermarket alarm system? which is cheaper/better?

your best bet, visit this site (http://www.rtautoparts.net), it has keyless entry module and remotes that you'll need for your car.

the one listed was for a 2000-2004? Must be different part number/plugs?

what year is your car?

1997

well, if you're trying to put keyless entry on your car, being that it's that old, I'd suggest going w/ an aftermarket alarm system that also has keyless entry. It'll cost more trying to put a factory system on then it will putting on an aftermarket.