A common problem for singles and couples is that most foods are way more expensive when purchased in small containers versus large ones. Sure, you can freeze a lot in individual serving sizes, but there are some things like fresh veggies, condiments, and perishables that just don't freeze well.
Two weeks ago, while we were getting ready to leave for vacation, I realized that I had the better part of a gallon jug of milk left and I couldn't bring myself to toss it (or guzzle it for fear of a stomach ache on the plane and a boost to my cholesterol levels). On a whim, I poured it into a clean plastic juice bottle that I had saved and tossed it into the freezer. I had read in an article from Cook's Illustrated that you can freeze heavy cream with little noticeable taste difference (although it won't whip correctly), so I figured Milk should work too.
As it turns out, it worked! When I got home, I tossed the frozen bottle into the fridge to defrost and the milk tastes just as good as when it went in. In fact, catch it with some leftover ice in it and it's even better because it's super cold.
So, next time you're staring at a gallon of milk that's 50 cents more than the half-gallon next to it, don't hesitate to buy the big one and freeze half. Just make sure you use a sturdy container with a screw-cap (pop-caps may release due to expansion pressure) and leave 1-2 inches of head space so the milk can expand without exploding the bottle. Oh, and don't defrost it at room temp for obvious reasons.