where to find pulley's under $10?

[ScouterMom]

Anyone have any ideas or links on where to look for replacement pulleys for a 70's starcraft ?

Starcraft wants $10 each for them, and at the number of pulleys it has, I'm guessing I would have to spend around $160!

I probably don't need to replace ALL of them, but haven't found anything that was reasonably similar to work.

Someone suggested patio door rollers - but in my area, checking with Home Depot, Menards, and Farm & Fleet, everything I find is either too small or too big. Plus the originals are riveted in, so it would be difficult to replace just the wheel in each.

Any suggestions?