I second whispering windz whipped soap. Especially since your friend could use it for a body wash as well as a shampoo. More bang for your buck

http://whisperingwindzfarm.etsy.com

If she wants to stay the grocery store route, there's also giovanni shampoos which are sulfate free (if you've got a target near you, they usually have the travel size bottles so she could test it out). A lot of grocery stores carry it now, as well as Target.
3A/2C
Mod-CG since 9/15/08
Lo-Poo: Whispering Windz Farm jar soap
Co-Wash/LI: Suave Tangerine
Rinse-out: EO Rose & Chamomile or Giovanni 50:50
Stylers: Pink Boots & Bioterra Gel