I saw this most awesome tool on a Facebook ad and new that I just had to share with my Tennis Metro family. Its the Obiband Tennis Ball Holder. Essentially its a belt, but if you're someone that has those favorite workout pants that don't have pockets this is the answer for you.
Especially in the winter, I have trouble with my tennis outfits, because my most comfortable workout pants don't generally have pockets. The Obiband solves that issue. Its a tight spandex beltish thing that goes over your pants, skirt, shorts or anything that doesn't have a pocket allowing you to stuff anywhere from 1-6 balls in there.
Pockets don't come too cheap however, $25 bucks for each one of these things. The good news is you probably won't really need more than one or two. There are two colors, black and white to keep your selection process simple.
You can grab them at a few tennis apparel sites, but the easiest option is to pick it up at obiband.com.
Check it out and let me know what you think, mine should be coming in the mail soon!