Think big. When you see a promotion or a way of buying something on a lower price, buy in a big amount. For example, in Portugal, the Marlboro cigars usually cost 3.50, but I import 10x10 packs from Azores at 2.30. It's an investemente. I don't think of buying Marlboro for a few months.
You can do this with many other things. You just need to have some money so you can import a large amount.