If you really want to try dpn's and simply cannot afford them right now, you can make them yourself out of dowel rods. You'll need a needle gauge card, which can be purchased inexpensively at Wal-Mart or a craft store. It has holes in it identifying which size needle fits into each hole. Pre-determine which size needles you want to use first, then go to Home Depot or wherever you plan to buy your dowel rod. Test different small sized dowel rods into the holes in your card until you find one the right size for the project you need. You'll also need some sandpaper. Take it home and watch this video (scroll to the bottom of the page). It takes some elbow grease, but it is very cheap, and easy.
I made my first set of dpn's using a dowel rod, and watching Amy's video. I still use them. I had to work with them a couple of different times until I got them sanded just the way I needed them, but once I did, they worked fantastic, and still do.
The sizes of rods available to you may vary each time you go to the store. I was able to find the size I was needing (for size 7 needles) on my first trip, but when I decided to branch out and make other sizes, I ended up going to a different local hardware store, as I couldn't find all the sizes I needed at Home Depot.