For java Fern and Anubias, there isn't substrate needed. You can attach those to ornaments, rocks, wood, whatever you want. Wisteria can be left floating, although I find that annoying. Crypts need to be buried and glass beads might not keep them down well enough.
When I first set my tank up I had only wanted to use small rock..then I decided to plant it and I just mixed in some gravel in the areas I wanted plants to be rooted down. You could try that if you want.
As far as lighting..Java Fern would likely do just fine until you can afford a light. It will be really slow growing, but it should survive at least. Even a desk lamp or one you can clip to the side of the tank works in a pinch..it would also give you more choice as to the plants you can keep.