I recently acquired a vinyl cutter that came with a reasonable cache of sign making supplies. These supplies included several 24" and 15" rolls of vinyl that I had no easy way of storing, so I made a quick rack to store most of them (the alternative was buying a $50-60 wall rack I had to mount that only held 16 rolls or a $200 floor rack). I played with the idea of making racks that would work with some cheap gondola shelving I picked up, but in the end I opted for a simple floor rack because it was easier, and significantly cheaper, to build.
16 M3x40 bolts - Perfect length for spanning 2 sheets of 1/4" material using 1" spacers
16 1" Spacers - I had some around for stacking PCBs on my Makerbot
16 M3 nuts - I've got a lot M3 hardware because of Makerbot projects
Rubber feet hardware - Picked up at Home Depot for $2
3-12"x18" Sheets of MDF - Available at Home Depot in 4'x2' sheets for about $6
15' 1" Schedule 40 PVC electrical conduit - About $2-3 for a 10' section
First you'll need to cut/drill your parts out. Get the design files and a more detailed BOM from the Thingaverse page for the rack here. I cut out all these parts out of 1/4" MDF on my laser cutter, but you could easily just use a hand drill and a hole saw to make them.
Bottom MDF Sheet
Top MDF Sheet
Cover MDF Sheet
Next you'll want to cut your conduit into sections. You can make quick, clean (but not always straight) cuts with a pvc pipe cutting tool, pictured below. I used 1" schedule 40 electrical conduit, which is a little under 1-1/3" in diameter in 12" sections. You could probably get away with shorter sections and conserve a little conduit.
After that's done, start assembling everything. Install the feet and assemble the top and bottom pieces with your M3x40 bolts and 1" spaces.
Next you'll install the cover, which will prevent the bolt heads from damaging the ends of the vinyl rolls. Use a couple conduit sections to make sure everything's aligned correctly then glue it to the top layer and clamp it down.
Now all you have to do is wait until the glue dries, remove the clamps, install the rest of the conduit sections and you're done.