You can purchase truck toolboxes from a variety of different stores. Basic tool boxes can be picked up at large hardware stores like Home Depot or Lowes. You can also check cargo stores and farming supply stores
We have a flat deck, with two small side boxes in front of the axle, and two larger side boxes behind the axle (we had the frame cut at 39" behind the back tire to accommodate these larger boxes). We also have two 46" wide x 4" deep lift-top tool boxes over the wheel wells....