Paul,
It all depends on what you want to get out of flying, do you want to get from A to B, fly around your local area, or just get your feet off the ground for the lowest cost.
Dont forget powered parachutes and gyros, have a TIF in them all to get a good idea of whats out there ( dont rely on others to tell you ). This is my opinion only but I have a number of hrs in GA, 3 axis, and powered parachutes. I have also had TIFs in gyros and trikes and I love them all but I cant afford them all. for me the cheapest form of flying is powered parachutes, and there great fun but they do have draw backs. but its cheap and I can keep it at home and take it where ever I want on the trailer ( you can also do this with trikes and gyros ) When I want to get some time in 3 axis I go out and hire a plane for an hour or so, that way I have the best of a least two forms of flying.
Good luck.