There's a ton of LED lights on eBay, some moderately priced. I would like to try it but I find the price a bit too high at the moment. They sure are energy efficient.
Most of the LED lights on ebay are... well, they are what they are. I got one from a business that is about $50 more than a comparable HPS system but should make up the difference in electricity costs in the first year or so.
5 cents from the noob lol... the flowers appear yellow because they absorb all colours of light except the yellow (or the colours that add to yellow would be a better description i guess) which it reflects, and your eye sees this colour.
Great looking plants, have you seen any difference between the different lighting sources?