I drink the Walmart stuff as well. If you buy one of those mixer bottles with the metal shaker ball in it, it comes out completely smooth. I only mix it with water though, if you put fruit and etc in it, probably not so much.

edit: http://www.amazon.com/Sundesa-BB28-SC08-BlenderBottle%C2%AE-Classic-28-ounce/dp/B001KADGMI/ref=pd_sim_sbs_hpc_1

That's the exact one I use.