I lurk here, but rarely post. Blanc, I came to this forum specifically to find out the same thing. So, I'll be waiting with you for an answer.

Gayle

I built a bed, about 5 years ago, using landscaping timbers. They are about 5 timbers high. The ones that are on ground level are rotting and will have to be replaced soon. The ones closer to the top layers are OK but some have spot rotting. When I redo their beds I will use untreated ceder or redwood. If I can will I use landscaping bricks to redo the beds. In the long run it is cheaper to do the beds in bricks and you only have to do it once if you do it right.

If you are looking for cheap and not pretty, you can always use large cinder blocks. They are cheap and easy to use. I will be building some raised veggie gardens next season using that system.

We're on the 4th year with our wood planks, and I expect we'll get a few more years from them. Another cheap-not-pretty way to do it is with hay bale borders. At the end of the season, pull the borders apart and mix it in for next years garden. Cheap if you have access to cheapie hay bales.

You can find free bricks on freecycle or craigslist.

I have a raised bed made out of untreated pine. I've been planting in it for 5 years and the wood is still good and strong.