I was going to convert an old rear wheel (Rolf/Bontrager Race Lite from... shit probably 2005) to trainer duty but the bearings are quite shot and don't look serviceable (spent some time with cone wrenches to no avail). So what's a good shit wheel for trainer torture? Something less than $100 preferably $50ish that won't see the outdoors.

A $50 option

Just tired of swapping axles and wearing down my good training tires.

Talk with your local bike shop. I picked up an older Mavic wheel that has cracks throughout the rim near the nipples, but for the trainer it works just fine and has good bearings, etc. Also, you might be able to score an older cheap tire that would work for your needs. Good luck!