If you are thinking of a low cost way of mounting a 2 meter, 6 meter or maybe a 10 meter ham antenna I would consider a tilt over tower. Yes you could construct one out of two by fours or maybe fence post. The nice thing is that most materials can be bought at your local hardware store such as lowes or home depot. Hey you could even build one out of heavy duty pvc pipe or grey electrical pvc pipe. Although pvc pipe would be good for very light weight antennas and I would definitely use guy rope to give extra support.
If you would like to learn more about tilt over towers click the picture below.
One bit of advise or should I say caution is to thoroughly check the area for any power lines. There are way too many hams or other people that have been killed by antennas coming into contact with electrical power lines. So by all means stay safe.