Harbor Freight sells decent dollies for fairly cheap.... I priced out building my own and it was more then I could buy a harbor freight set for. Decent caster wheels get expensive. You could check places like E-bay or Craigslist for used dollies or casters to help save on costs depending which route you wanted to go. I did get a bunch of casters from E-bay to use on other projects. The ones I got are from shopping carts and are pretty sturdy for the few racks / stands I have made. Good Luck.
