If 12 x 20 feet, I'd go with HID lighting.
If 12 x 20 inches, I'd perhaps go with the LED's.

Although a few gardeners are having some successes with LED's, I much prefer HID lighting. Especially if new to growing. HID's are easy, proven and reliable. Each type of light comes with benefits and consequences.

Whichever way you go...get the best you can afford. E-Bay crap is often...crap. If you have any questions...ask here before hitting the "purchase" button. It might just save you a bundle on an ill-advised purchase.