If you're looking for some supplemental lighting, the big box hardware stores have some T5s that are affordable. But they don't have a good variety of fixtures that are designed for grow rooms. My local hydro shop carries a few different ones that are worth paying a little more for IMO. The larger fixtures at the hardware stores are mainly meant to be mounted directly to the ceiling and light an entire room. So the reflectors aren't designed for maximum efficiency when hanging right over plants. Those stores also sell some T5 lights that aren't high output, so be careful about that. T5 HO is what you want for growing.
Online definitely offers the best variety and prices if that's an option for you.