They sell anything like this here?

[TurboDan]

This looks pretty cool. But it's from Australia, which would presumably require some big shipping costs.

https://www.maxtrax.com.au/

[TurboDan]

I'm an idiot. I found they distribute to a few places in the U.S. Blah.

[Soup DeVille]

If you google them as "sand ladders," you get a lot more responses, since that's what they've been called for years.

[Rupert]

I've used chunks of plywood before. I bet those rubber restaurant mats with the holes in them work well, too.

The advantage being that they don't cost $300.