DH and I used the small boxes (1 cup?) of Parmalat milk the last time we bike toured. It's ultra pasturized, so it doesn't require refrigeration as long as it's closed. It worked great for cereal and mac and cheese. I'm not sure if smaller grocery stores carry it, but all of the bigger ones around here do.

What about meat or cheese from the deli counter? I imagine they'd sell you just a few slices for a meal. As long as it's heavy enough to read on the scale....

Pill or toiletry containers work well for small amounts of seasonings. Look for those little jars that screw together into one big cylinder. We put cooking oil in a sqeezy bottle with a pull-top (like you'd use for shampoo while traveling) and then into a zip-loc bag just in case!