The kind of greetings cards I like to make are ones which are quick and simple, ones which can just be whipped up in batches whenever I feel like papercrafting (usually when my to-do list says "vacuum" anything). Knowing that they often lead to further purchases, I try not to buy too many craft magazines, but they do have their uses in inspiration and ideas, and, sometimes, free gifts like paper packs and ribbon attached to the cover. If you can't resist craft titles, you may well save money per issue if you take out a magazine subscription and if you do this online via Top Cashback you'll get money back on your purchase.
As with sewing projects, I am always tempted to buy the exact beautiful materials featured in the photographs, but instead make do with what I already have and adapt the card accordingly. The most important thing I've found is that, like with so many things in life, you need a system. With card-making, that means it's all about the layout.
Pick a motif that suits your recipient and mount it on some colour-co-ordinated card or stiff paper, preferably plain. You could cut a motif out of a photograph or magazine, wrapping paper, an old card, or printed off the internet, such as these free papers at The Making Spot.
Using up scraps of paper is a very frugal way to make a card. Just make sure they are all in the same colour scheme. I find that three stripes of paper works best. Alternatively any odd number of stripes. You can also glue ribbon here or use patterned tape.
Finally, line up the frame of the motif with one of the stripes and glue it in place. Simple, effective, and frugal: the perfect card combination.