So, brand names, Belden, Alpha and such?
Mail order from big distributors always sucks; it's alright if you just need a few and are buying other things too, but that's about it.
More specialized distributors (check for local electrical supply stores?) may have better deals. Or there's always Amazon and such. You may even find distributors through their Amazon stores. Check the source carefully!
Alpha 3071 and 782001 come to mind (600V), and any other mfg equivalent or similar will do. Hookup wire, machine wiring, general-purpose keywords like that. I'd prefer >90C max temp rating, which is the upper end for PVC then other (usually more expensive) types take over. 20 or 22 AWG should do for pretty much anything.
Tim