I have an album of my cage building process on my profile here. And if you search "homemade cage", "handmade cage" or "melamine cage" you should come up with a handful of threads with pictures.
I used:
*Kiln dried pine--shelves cut at store. You could use other woods, like Poplar, but they are more expensive and harder to cut/drill if you have light duty tools.
*Melamine--cut at store
*16 gauge 1" x 1/2" welded wire, galvanized after weld--found at Lowes
*Braces (T and L shapes), hinges, screws, washers, door locks etc.
The tools I needed to buy were:
*Drill--light duty will do
*Wire cutter
*Staple gun--to staple wire to frame
*Hand saw, to cut the smaller wood of the frame. Not needed if you get all the wood cut at store and make sure they cut it the right length.
*Sandpaper--not really a tool, but...
*And the screwdriver, hammer (to bend wire around wood) and wrench I already had.
My biggest piece of advice would be plan out everything!! I had to do some things over and wound up buying another roll of wire because of it. Drawings and lists will be a huge help, schematics are key. Plus, measure multiple times before you cut or drill.