or you can do what i did in high school......carefully peel away (or you can steam it off with an iron) the protective styrofoam cover under the top of whatever you buy (if it has one, the creatine used to) and then dump out all the stuff into another container......then fill it back up with sugar and glue the styrofoam protective thing back on and return it as new. with this method it's better to buy a multiple items at the same time and do them all so you wont have to be back for awhile. but they probably wont hassle you if its new.
then you can enjoy looking out over your fellow gym compatriots and snicker at which one's getting fatter off all that sugar he thought was creatine.