i just built a 4x4x2 cage for 20 bucks. i already had the ply wood, but its cheap and it comes in 8x4 sheets. buy 5 sheets of 8x4 plywood, put it together like a cube, seal it wiht polycrylic, put glass doors, i used screen doors for price issues and places for the lamps. i did all this in just 5 hours of work, and now im waiting for it to dry. you could easily build a 8x4x8 enclosure for cheap and he will be super happy.