Ditto on the straw method used above, it's highly effective and cheap - even commercially viable and offers reusable containers. I do wish that there was something similar on the market that offered a bit more durability for the caps without relying on tape or glue. If commercially produced I envision a collection of 5-10 straws with a clear plastic "wallet" made out of 3mil to 5mil plastic with indvidual slots for each straw it to slide into with a fold over to help protect them from getting scattered about. It'd be the ultimate reusable spice kit pouch and empty weight should be <1oz. One of the major up sides of the straw method is the ease of control for sprinkiling without relying on divider with a bunch of holes in it to control application.
Other options - I have a vacuum sealer, I sometimes bother to make up packets the similar in shape but smaller dimensions to the crystal lite on the go, propel single serves or other powders that are simply a tube-ish packet of powder in a standard plastic wrapper. Just make sure the miniturized packages offer convient single serve portions and you are set.