http://www.ragwing.net/ has several sets of plans for sale. These are all wood and fabric aircraft, so that would make them inexpensive. The thing is that you really have to know what you are doing to build an airplane out of wood. I haven't had the pleasure of working on a wood/fabric airplane yet, but I have had some training. Working with the fabric takes a special touch and a lot of patience. Get ready to sew! Even so, I would love to build their RW1.

Beyond that, Google is you're friend.

Edit: I forgot to mention, some of the airplanes on that site are made with steel tube instead of wood. If you can weld, this may be a better way to go.