Acrylic is really easy to work with. You can buy some 5/16ths or thinner acrylic, cut it with a jigsaw (easy) or, if thin enough, use a scorer (more difficult), and then use a chemical bond to connect the pieces. I use two corner clamps to bind pieces together, and either epoxy (fast, look doesn't matter), or solvent weld (looks better, more difficult to do well) the pieces. You could make a box like that in 20 minutes for just a few bucks.
!c