Well, we did our 12ft X 18ft run in wood and hardwire cloth. We were going to go cheaper, but decided to do it once and do it right.
For the wood, we used landscape timbers from lowes and they were no more than $5 each, plus they were basically the same thing as a 4X4 post. Plus they are already treated.
Then I ordered my hardware cloth online at
CSNSTORES.COM and the shipping was FREE. Plus.... I saved almost 50% by ordering my hardware cloth online.
3ft X 100ft roll is $84.71
2ft X 100ft roll is $58.46
We put the post 3ft apart for the 3ft wire and then we used the 2ft wire for the top and doors. All in all it was pretty cheap, strong, durable, and looks great. We have all kinds of preditors in my area and since I'm deathly afraid of snakes, the hardwire was a must for me.
ETA: We also had to pick up some 2X4X12 to put across the top of the run to hold it securely. We plan to put a tin roof on top of that to help keep the run dry in the rainy seasons and provide added shade for the chickens.