i have a MPFS-Disco-kit Rev 2 aka PolarFire SoC FPGA Discovery kit made by microchip technologies, heres the link for this one:
https://www.microchip.com/en-us/development-tool/mpfs-disco-kit. My price:50$ O.B.O
The second Board is a PYNQ-Z1 by Xilinx heres the link: https://www.digikey.com/en/products/detail/dfrobot/DFR0600/10136559:My price:100$ O.B.O
The third board is a Altera DE1-SoC with Cyclone-V processor. https://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&CategoryNo=167&No=836. My price: 150$ O.B.O