Alibaba.com is where resellers go to buy stock (Solis-tek, Galaxy, Lumatek, Apollo, pretty much every major ballast brand is just rebranding Chinese made ballasts) in the hundreds/thousands to be shipped by ship in cargo containers. However, you can request a "sample" of a few ballasts which I'm in the process of doing and they'll sell it a few dollars above bulk pricing by DHL overseas. Shipping is quite expensive but still cheaper than buying rebranded shit for double the price in markup. The FOB (bulk price sent to a ship) price for these ballasts typically range from 60-105$, and then they get marked up to $100-300.
Solis-tek is actually just a front owned by a Chinese manufacturer for example and outside of NA their ballasts sell for $95 for 1000W under the Helius brand compared to ~200-300 over here under the name Solis-tek brand. Galaxy also sources some of their ballasts from the same company Solis-tek operates from - namely Jayo Technology.
http://tinajayotech.en.ec21.com/1000W_Electronic_Ballast--9223328_9223329.html