I've made my own; too much botheration for my interest in cooking. YMMV. I buy the stuff from Sam's club and keep it everywhere--my glove box, briefcase, drawers at work. It's one of the few foods that almost improves after a summer of baking in the car. (And way cheaper to buy in bulk than to buy in an emergency quick-stop run, where you can't always count on the house brand being sugar free.)

Recognize home-made might be even cheaper still. As noted above, still too much bother for the way I live.