Trying to make a DIY dolly and cant find decently priced skate wheels ($15-25 for 8 wheels including bearings). These were widely available during the summer time but I was not ready to make a dolly then.

Have you got a "Play It Again Sports" in your area? They buy and sell skates.

Quite possible they're not carrying them this time of year though. Best idea I got...

Or put a 'wanted' ad on Craigslist.

There is a Play It Again about 8 miles from you on Glen Cove Rd in Carle Place, next to Eastern Mountain Sports. They have more wheels than you can shake a stick at. Got mine there. Make sure you get bearings for them.

As a former competitive inline skate racer, try contacting some of the inline skating clubs in your area for some leads on getting wheels...

Try Ebay too.