Need recommendations

Hi all! I'm absolutely new to electric skateboards and very interested in owning one.

What I'm looking for is a board that can go across a grassy field. I'll only be using it at least once a week for short distances.

I'd prefer brushless over brushed, 36"-42" inch long board, and (here comes the punchline) be around $500 or less.

Does this board exist or do I need to build it myself?

Thanks in advance.
Wolphe