Low-cost cover for leftovers for fridge
Actually, I didn't want to be accused of making inflated claims for the service, but this system is actually no-cost.
When you have your leftovers collected in a soup bowl, etc., slip the bowl into a bread wrapper.
If you ensure that a good amount of air is trapped, then twist the open end, you'll avoid having the bread wrapper dip down into the leftover. Tuck the twisted end of the bread wrapper under the bowl, so that it stays twisted and the air balloon stays in place.
"Cheap, cheap," says the little birdie.
Good wishes for finding savings in all of your activities.