LEDs are the best for small space growing and the extra cost upfront is made up fro the 5+ years of use u get from them. cfls and hps need to be replaced every few grows, hps have high ,heat to deal with which makes them ill suited for small spaces without proper ventilation which also adds to their cost. CFLs whil much less heat then hps lack penetration so u end up needing a lot of bulbs to effectively cover ur plants especially during flower its my opinion that equal wattage LED will outperform CFL easily. Cheap LEDs are available on ebay just do some research into what makes a unit good and what dosent.
Now that 5w bulbs are more common 3w units have taken a nice nose dive in price and while 5w bulbs are better for canopy penetration that are 5x or more as expensive, 3w units grow weed perfectly fine for their cost though as long as ur looking at 6+ band spectrums and quality sellers. id say something etween 180-300w is what u need to get some nice nugs out of 2 autos regardless of what lighting type u pick.
don't scrog them autos don't respond to scrog as well as photoperiod plants in my opinion. 3 gallon pots should yield 2-4' tall autos with no training under that amount of light as logn as ur using a superauto and not a lowryder or dwarf strand