Well dude take a XILINX XC2V8000 Virtex - II FPGA has around 10 million gates, Its only in the protype development stage, i guess its around few thousand $$s as its jes the protoype and when it reaches mass production the cost wud surely reduce.
Sometimes the maximum gate count don't give a clear idea about the FPGA capacity, I think that for Xilinx the Slice count is more efficient than the gate count