30ga cube lighting suggestions...HELP!!

[bues0022]

I need some help trying to figure out what to do for lighting for my 30 gallon cube. Dimensions are 23H x 18D x 20W. I'm planning on having a shroom/softie tank so I can get away with less light for now. My problem is trying to get light on there for as little $$ as possible both for setup and electricity cost. To put dimensions in perspective, the tank width fits an 18W NO light strip from a 10 gallon perfectly.

I have access to putting two NO strips with good bulbs on the tank for only $30, but I'm concerned of the light penetration - will it go deep enough. The sand bed is 19" below water line.

What are your suggestions for me? I can DIY things, so maybe a DIY PC fixture? This might get more costly than I want to make though. Maybe someone has something laying around that you don't need? Maybe I will actually be fine with the NO lights because they have decent color bulbs in them. What are your thoughts?