You know how every recipe ever that uses tomato paste only calls for 2 tablespoons? Maybe 4 if you're lucky? And those pesky cans come in the 6 ounce variety...which is 12 tablespoons, by the way. Not terribly handy. My personal favorite is the pizza sauce one that calls for 8 ounces. Grr.
So here's the easy way to keep the paste on hand, pre-measured and ready to use:
just freeze it. But don't just chuck the can in there like Martha says, that means you will have to try and saw a frozen lump apart, or even worse, try to pry a frozen lump out of a frozen can.
Take your handy dandy tablespoon measuring spoon, and make some glops on wax paper. 2 tablespoons is one ounce of paste, so make sure you have room in your freezer to lay a decent sized sheet out for a good minute. Ok, an hour, but who's counting? I, being very organized, forgot, and did the packaging part a day later. Or two. Close enough. Once they're frozen through (or once you remember that you're doing stuff and get back to it) pry them off the wax paper (it's easy don't worry) and either pack them two by two with a foodsaver, or wrap in wax paper and put them all in a ziploc. (Wrapping is essential if you aren't vacuum sealing as they'll stick together far too easily).
Label, pop them in the freezer, and use one or more as needed. They thaw in just moments since the paste has a very low water content and they never get that hard frozen state going.