1000bulbs.com has been pretty good to me, they have everything you can think of, 13 watt cfl's are .99 a pop. the 42 watters are around 5-6 bucks as well , worth looking into for sure. they even give you all of the specs and ussually 3-5 different brands of each watt bulb your looking at so u have a choice of different brands and/or specs as some have more lumens than others, i love the site.

the snake