I use PVC as I can't afford wood.
I went to the local reuse shop and bought a couple of PVC pipes, the cost around $10 each and two of them were already painted!!!!
Wooden ones usually cost AT LEAST $35 each for unpainted ones, painted ones start at around $45.
I find that they do blow away if the wind is strong, this can be avioded by putting stone into the ends(above the jump cups) so that they are more secure and require more of a knock to knock them down but they do fall down which makes them safe.
I had a horse who had no respect for poles, he would knock them down willy-nilly every wich direction. I used a PVC pipe, he stood on it and it did not shatter, it dented and made a noise, this freaked him out and he no longer hits fences. I inspected the pipe and it showed no cracks etc.