36x24x24 Micro Grow, $40 for Lighting , and Go ... Suggestions ?

I am just about done building a 36 x 24 x 24 inch micro grow out of a 276 lb test cardboard box from Staples.

Lined with Reflectix and Aluminum Tape.
2 4x4 Exhaust Fans mounted top back (ripped out of old laptop desk)
1 4 x 4 Passive intake front bottom.
Seams reinforced with grey duck tape to minimize light and air leaks.
Key stress points reinforced with steel staples (love my staple gun).
1 Carbon Air Filter

Now to the lighting. I was planning on mounting a previously purchased 18 inch T5 HO on one of the back corners. I need an overhead light though as well. Would a 26 W HO T5 CFL Bulb mounted top side (horizontal ) be enough for veg in that space (when combined with the 18 inch vert).

I can spend $40 max. My big concern is excess heat but with a low budget, I'm not sure what my options are.

Suggestions welcome.

you could veg with those lights no problem depending on how many girls you are running.
or you could order a few 42w cfls and have the 18w t5 above the plant

I would add another lil t5 or something equivalent.
You could get short 18"-25" t5 under cab lights from hd or walmart for like $20.
Also from my experience with duct tapes you either have to double it up or more for it to be really light proof.
Good luck