For my 10g planted betta setup, I purchased a glass hood then two 15 watt Strips. It is quite bright now, I'm at 3WPG, which is nice. Each light fixture was about $20 and the glass hood (my second, I'm a clutz and dropped the 1st, a messy clean-up that was!) cost about $7. Of course, they are outfitted with full-spectrum bulbs. With the two strips, I can experiment with varying the amount of light during the day. I have only one stip on during the early morning and before I go to bed, then both are on for the full day. I still don't grow very many light hungry things, but my cryptocrynes are very nice and my anacharis isn't stringy. I find I have to prune a lot, though. They're do for one already and I've only had the plants for about 2 weeks. I'm not having a big problem with algae now, but time will tell.
I also have a 15h with a similiar setup except the second fixture is not a standard 15 W but a twin T-5 24" which sits atop the glass tank hood. The tank is considerably deeper, so I grow more low light plants in that tank, though it still gets about 2.87 WPG. As it is an older aquarium, 2 years, it had more of an algae problem. It also had plastics first then I changed to live, and I lost a lot of the algae and the ugly green stuff is replaced with only a little of the brown. I scrub it off when I do my weekly tank duties. That tank could use some pruning too.
But I am certainly no expert and there are people on this board with far more knowledge than I.
