you can buy loose tires CHEEP online fromt he likes of tire rack and others. Do those Harbor Freight machine work? HELL YES! IMO the key to DYI mounting of tires is to not be afraid to lube the hell out of them. A mix of Dish soap and hot water works well. Additionally not forcing the tire processes. Finesse is the key. you should practice on some junk/bald garbage a little before you try on your good stuff.
The biggest problem with the machine, is the star that holds down the wheels, it had sharp points on it, so I ground them round and put a big piece of rubber under it, that cured it digging into the wheel. The tire bar, they sell better ones for $100 on the net, but with a bunch of UHMW I have this one working well, it doesnt scratch anymore. And make sure to put something down when you break the bead.
I like it, and its fun to do.