A couple of weeks ago, I received the new Ganglion board from OpenBCI. This 200$, 4 channels EEG amplifier looks quite promizing. The board has a very interesting design. They got rid of the expensive ADS1299 EEG front-end for a fully custom solution made of discrete components. The amplification relies on the AD8237 differential amplifier and the digitalization is achieved by the MCP3912, a 4 channels, 24-bits ADC designed for power meters. I happen to know well this ADC since I also use the 6-channels version for my own EEG amplifier.