Are you talking about light bulbs? The aquarium light bulbs found at Homedepot have a variety of watts and stuff and I think they are in the right spectrum. You can't just stick any watt light bulb into your light fixture, however. It wont work.
There's nothing wrong with having a low light plant tank. I love mine, it never grows a speck of algae! You just have to be conscientious with plant choices.