On a small tank like that, it is probably hard to beat compact flourescent light bulbs in terms of expense.
Those clip-on shop light dome-reflector things they sell at Home Depot/Lowes (I think they are sometimes called brooder lights/lamps) seemed to work pretty well as reflectors when someone posted a comparison w/ PAR readings. plus, they are like 6-10 dollars.
If ghost shrimp are the same thing that I remember back in the 90's, I'd advise to go with the cherry shrimp. The ghost shrimp never lasted very long in any tanks I had set up, where as a lot of people seem to be able to keep a breeding population of cherry/etc. shrimp.