Lowes and Home Depot have been the two most major stores I've been to for supplies.
It's also nice when you have a specialty shop nearby which sells products for growing.
For the veg cycle I added two 6500K daylight 100 watt CFLs and they began to grow like mad.
I would suggest going all CFL because the produce higher lumens and use less electricity. You can also find 150W CFLs for about $10 each for when you want to throw them into flowering. They range in the 2700K scale which is what you're going to want.
If it were me I'd add 4 of them at least, just because I love the CFLs and they've proven to be excellent so far for my grow. I just added two LED panels (one is a UFO), and will be adding another today.
I need to build a bigger room ASAP because I'm now up to four larger plants and they're going to start smelling pretty soon.