Something to try/look for/have other than the Crystal Light:
4C Totally Light 2 Go
They are flavor packets (admittedly they flavor STRONGLY - I use one stick for 24oz of water when the recommended says 16.9).
They are made with Splenda, no aspartame! Yay!
I actually have been using these for years (before IP) because I have a friend who has epilepsy and can't have anything with aspartame in it at all because of it's possible neurological effects.
Anyway, check 'em out. Lots of flavors (tea, lemonade, pomegranate blends, fruit punch, etc etc)
I would think they would be possible to find in most grocery stores (here on the east coast I have found them in Stop and Shop, Big Y, Shaw's, etc).