Free: Contests & Raffles.
How big is the serving size?
How about just a small, wide-mouthed Nalgene bottle, like 250ml and just scoop out what you need, no waste, no fancy packaging.
Film canisters.
You can order mini zippys in any size you want pretty much. i get a sales magazine I think called just "Plastics" that has about anything plastic you could ever want. There is also mini heat seal bags that could be used like a vacuum seal bag but probably cheaper and made in smaller sizes.