I'm a little late to the party with this info but I thought I'd post for those contemplating on buying versus building their own for a one-off project.
I made a cabinet using parts that are readily available from our local stores (except the gloves). Cost me about $60+/-
I bought the largest rubbermaid container I could find from Walmart and a pair of toilet flanges from Homedepot. I used the flanges to trace two holes in the container and cut the holes out using a jigsaw:

Next, I screwed and caulked the toilet flanges to the container:


I bought and installed a brass valve and washer in the side of the container for the blasting media hose:

and then ordered blasting gloves from Harbor Freight for $6 and installed them over the toilet flanges using hose clamps I purchased from a local hardware store:


Next, I connected the hose and blasting nozzle to the valve inside the container:

and then purchased a piece of glass from Homedepot for $4 (plexi was too darn expensive), cut a hole in the top cover of the container and taped it on both side:

I used the cabinet to blast the old paint off of a FN FAL kit i purchased prior to parkerizing the parts (manganese phosphating)
It had a few qwerks like keeping all of the blasting media in but it was good enough to clean a whole rifle.