Clothinglabels4u.com offers ready-made size tabs. They sell them in packages of 10 on up. I have had nothing but great experiences with them; they usually ship the same or next day.
If you're looking for "brand" labels, you can either print them yourself with an inkjet printer and fabric paper (or fabric on paper) or hire someone else to do it. Your choices then will be either woven or printed. My first batch was printed because I wanted to see how it went and if I wanted to upgrade to woven. Mine were doing by
custom Couture Label Co.. I also had them print my first set of hang tags. They've recently added woven labels to the mix, which is nice because the volume requirements are pretty low.
Actually, that's one of the biggest challenge with woven labels -- the minimums. But there are companies out there that specialize in small orders. I switched to woven once I knew I was selling my creations. I think they look more professional and they hold up so well. (My printed labels have done fine, BTW.)