Your best bet for a cheap wheelset is to check out a local bike co-op or bike shop. They should have a lot of 26" wheelsets lying around. Or check out Craigslist.

If you want to stay on the internet you can order these Velomine wheels. Sun rims with Deore hubs. Good quality. That's $149 for the pair. 7 speed compatible. Grab a 7 speed HyperGlide cassette to go with it.

Or you could build your own wheels and learn a valuable skill.

Edit: By the way that '92 970 is a sweet bike. Lugged True Temper goodness!