Here is mine I got the wood from Lowes just plain ole 1 x 3 for uprights and 1 x 2's for the resr of it. Put cross pieces to help hold the grids on bottom then zip tied them all together. Here is the link to my pictures and if you go to the Photo Galleries above and click on either closed cage or closed multi level you will find more pictures of other peoples cages. Here is the link to mine
the boys new cage - Guinea Pig Cage Photos