I buy Tupperware type containers at the Dollar store. All different sizes are $1.25 and I don't have to worry about getting them back.
Same thinking I guess... But I go through a butt-ton of sour cream... And a fair amount of Cool Whip... Might as well save the containers for that purpose.

There's probably eight medium sour cream jugs sitting in my tupperware drawer right now. I just seen the stack, as I used one to send my son on his way with some chili and corn bread the other day (which I am fairly famous for)