Well, while other reps are pimpin, I might as well throw my 2 cents in here. Rampage - comes in a small bottle, is a short-lived stim (plenty long enough for even a 2-hour gym trip), and is pretty dang cheap. It's often overlooked, as I think it's the most senior AX product out right now that hasn't been retweaked. If you're in need of something to go-go-go while you're on the go-go-go, then this'll work well for you. Stash it in the glove compartment, in the gym bag, locker, desk drawer, or wherever.
Just keep in mind that although these individual packs may be handy, you are definitely paying more per serving for this "convenience". Look at similar products and compare price/dose and you'll see that you will always pay more for packaging. Not to mention that you usually get a lot less, simply due to the bulk of the packaging.