Cheap Communcionations

How simple (read cheap) can megabit communications be over power lines. Internet0 seems to have not taken off. Not sure why. All of the devices for communications over power lines that I can find seems to be directed at broadband stuff, the chip sets to implement them are all > $20, OFDM, WiFi derivatives and the like ..... I'm looking for something more like < $2 for the chips/transistors,resistors etc. Generally I need a small miroprocessor as well, say Atmel or PIC, to do anything interesting.....so I'm thinking