The Terasic series are great, especially if you aren't too fussed about peripherals on the board. The DE0-nano has a decent sized FPGA and SDRAM for less than

The Terasic series are great, especially if you aren't too fussed about peripherals on the board. The DE0-nano has a decent sized FPGA and SDRAM for less than $100. There is also a SoC variant of this board coming soon with an integrated ARM subsystem.