It's always a pain when I want to add a bit of cream to a sauce. If I buy a half pint, 90% of it goes to waste -- I just don't use cream that much; a couple of tablespoons in a sauce once or twice a week. So I make do with milk and cornstarch, but it's not the same.
It occurs to me I could buy those tiny plastic and foil containers of half and half or cream they serve at diners. Do they need to be refrigerated before opening, or are they shelf stable? Also, and most importantly, where do you get them? I couldn't find any on the web.