Buy foil and plastic takeaway-style cartons
No, I've not gone mental.

Cooking for two generates a lot of waste so cook for 6-8 (or more people) and then put the extra portions in a foil or plastic tub (depending on whether you'll reheat with the oven or a microwave.) Freeze the extras until when needed.

For a very small amount of extra effort (you were cooking anyway), you'll soon have dinners ready-made stocked up in the freezer, which is great because you can have a week living on them and just buy accompanying vegetables, which is a monster saving in time and money for that week.

We bought a second freezer to be able to make the most of this.
(ThatNiceMan thought he was being funny, Fri 11 Nov 2011, 15:40, 3 replies)

I made shitloads of pasta sauce with all the spare tomatoes from our garden
Freezer is full of tasty, tasty, organic tomato sauces :)
( emvee cruor deo cruoris, Fri 11 Nov 2011, 15:42, closed)

We save ours whenever we get a carry out, not often ;)
But remember this, once the content is frozen a quick whizz under the tap and a squeeze will release the contents freeing up the container for further usage. Simply pop the frozen block in a cheap freezer bag before stacking your freezer drawers in autistic and rotatable style ;)
( blaireau69 , the Cumbrian Travis Bickle., Fri 11 Nov 2011, 17:05, closed)

Plus
Your freezer doesn't work as hard when its full either.
(yourmumonastickwithmintsauce, Fri 11 Nov 2011, 20:47, closed)