Rohn 25 (Score 2, Informative)

Buy some used rohn 25 or similar at a ham radio hamfest or swapfest. The tower comes in 10 foot sections and is self supporting to 60 feet. Put half a section in a yard of cement and go up from there. A hinge bracket at the bottom rocks all.

And if you have more money to spend get a Hazer system so you don't have to climb the tower to get your antennas to the top.