12 weeks test E is a good beginner cycle, and is pretty cheap honestly.
If you can't spend a months worth of food on the gear you want to use on a cycle, i'd wait until you can.

Agreed with the others--
At 6 foot, you are pretty light, low body fat or not. I'm 5'8.5" with 162lbs LBM...
You have almost four inches on me and we have about the same LBM.

If you're a hardgainer, you need to focus your efforts on eating MORE. You might think you are eating a lot, but some people have to eat more than others to grow. If you don't eat enough to grow off of AAS, you will simply shrink back to your previous size once your cycle is over (or not really get any gains at all).

Good luck!