I bought a cheapo light bar from amazon (combo flood and spot light), and it works just fine. Just read the reviews, and pick the one that fits your budget.
Keep in mind, when buying a budget light bar. They may have waterproofing issues, and the bracket themselves might not be the best quality brackets out there, and the light bar switch tends to be cheaply made.
As far as light output, mine seems plenty bright for a cheapo light bar. It works very well for most offroad situations. I remedied the switch by using a Bluetooth lighting system, so no rat nest of wires.
I don't care enough about the light bar to let the watertightness bother me or the brackets bother me.
Also keep in mind, if you are mounting this on a full roof length roof rack, and the light bar is mounted close to the windshield, prepare for a lot of light splash back on your hood and to light up the dust on your windshield. It's annoying. Ideally, you want the roof light bar mounted 6 to 12 inches further back away from the windshield to minimize light splash on your hood.
I also wanted to add, that a roof mounted light bar is pretty much useless if you don't venture offroad much, due to current laws regarding offroad lights on public highways.
YMMV
