RickCorey_WA wrote: Those look good, but $4-5 per linear foot, 10" high?
I like concrete paving stones stood on edge, around 1" thick and 8, 12 or 16" high. Around $1 per linear foot. They are heavy to haul, but very easy to re-arrnage and no tools for installation. One of the few materials even more eternal than plastic!
The only stability comes from leaning them into the bed a few degrees. If you don't tidy the "leaners" up every few years, they start to look straggly, but I'll do that toi save 75% - 80% on the cost (or to get beds 4-5 times bigger for the same cost!)
They do tend to dry out faster on the corners, I guess because concrete "breaths". Now I save plastic bags that soil amendments come in, and cut strips to line my corners so they don't dry out fast.
Plastic liner also keeps the little open triangles on the corners from leaking soil, or you can chink those with gravel or a stick. "One of these years", I'm going to get out my angle grinder and kind of "mitre" the corners so they meet flush.
They come in brick red or gray, but someone piojtned out you can dilute house paint and color them cheaply. "Sand color" looks nice.