It is worth at least commenting that price should be weighed against other considerations. Above all, how much of a pain in the ass will it be to work with a given board. This goes hand in hand with the availability of documentation and schematics.
A google search for "cheap FPGA" yields more than I expected.
I remind myself that my FPGA journey began with the $12 EBAZ4205 bitcoin miner board. It is important to choose hardware that you are "up the curve" with as far as the toolchain in particular. Otherwise a bargain may not be such a bargain.The most interesting thing I quickly tripped over in the first link above is this:
The RV901T uses a Xilinx Spartan 6 FPGA. Other boards like the Colorlight 5A-75B and 5A-75E use a Lattice ECP5-25 FPGA which can be worked with using an entirely open source toolchain, and has been reverse engineered.I see these on AliExpress for $16 and something called the RV201 is a replacement for it. With shipping you will pay $20. It is intended for use driving a big LED screen.
I ordered two of the RV901 cards, shipping for both was $10 and at $16 each, the total comes to $42, so each card will cost me $21. Order placed 5-13-2022 on AliExpress.
Tom's Computer Info / [email protected]