The Loongson 3 devices are hard to get, although apparently you can get them from China; the 2f devices are slow and a wierd version of mips, dont recommend.

The easy to obtain cheap Cavium is the erlite-3 but it has the most non standard usb which means you are pretty much stuck with a tiny amount of storage.

Soft cores are a bit slow, although have seen CHERI running and it is cool. (Risc-V runs NetBSD, at least partial port, not FreeBSD yet).

So there is no useful easily obtained dev device for under $200 (although Imagination did seem helpful on twitter on helping get stuff).