Denise on the PTI forum asked for some pictures of how I store my PTI dies - so here they are:
I get the foam board at Michaels - a package of I believe 5 sheets, 10x14, made by Elmer's. I cut the sheets down to 81/2-9x14. The magnetic sheets are made by Quickutz and have adhesive on the back - with a 40% off coupon at Hobby Lobby, a package of 6 sheets (4x12) are a little under $5. At some point, when I have some free time (HA!) I am going to label the exposed foam to the left of the magnets so I can quickly see what dies are on what sheet.
I then just store them on a shelf - or actually in this storage unit I bought from Michaels that sits on my shelf. You could easily buy larger sheets of foam board and cut it down to any size you like - perhaps 12x14, and then put three Quickutz magnet sheets on each board. I like this system because I can quickly flip through to get the die I want, and to put the die away all I have to do is stick in on the magnet. Plus, if I am taking my crafting on the road, I can just grab all of the boards and put them into my travel case.