If you can get a concrete truck to your back yard, go with poured concrete. No great skill or physical strength needed for a 3 ft wall. Won't rot or burn. Lasts forever and can be covered with a veneer of choice to make a good looking wall to boot.

railroad ties are better than landscape timbers, they last about 10-12 years before needing to be repalced, they cost aboput $10 a peice, landscape timbers make a weak wall at 3' tall

What do you think the concrete with veneer would cost for a wall of this size??? We have had a few quotes that were substantial..... we live in a small town in California so I'm just wondering what the rest of the world thinks?

ps - - thanks for the input...