You can buy a S3E250 board, with FPGA + SPI flash and USB programmer/UART (FT2232) for US $50: http://papilio.cc/index.php?n=Papilio.Buy
. The S3E500 is a bit more expensive, but IMHO is worth the money (USD $75).
GadgetFactory is also working on new boards, based on Spartan6 with integrated SRAM. Those will be amazing for sure, I haven't got my hands in one yet.
Even if they are marginally more costly than Mega, they do offer you other possibilities - one is you don't require that much external components (digital) for your projects. Disadvantage is lack of internal ADC - you can use a SPI one if you wish, and they are cheap and with very good performance (500ksps).
So, I guess is time for you to wake up