Conmoto,
It refers to selling a product at little or no profit, or even at a loss to attract customers to a new product or company.....often times to get a good public response and "buzz" for the company. Not really a derogatory term, unless intended that way.
The Gaia feet alone are $50 each retail, or $300 for all six, the WBT binding posts are $45 each or $180 for four.....that's just about $500 just for the feet and binding posts per pair. It appears the caps, resistors, air core inductors, and wiring are also rather high grade....though I can't recall exactly what they are off of memory. Not sure about the driver costs.
Overall he seems to be selling a very high quality product for an extremely fair price, Having no middle man (dealer network) also helps greatly.