Yah, I don't keep a can in my TJ either as I don't need it very often. Maybe three or four times a year? We can have a whole discussion about bugging out though at another time in another place maybe. If you get into an "Oh shit, we need to bail out!" moment, I always advize that body bags be part of your bug out gear. I don't carry any and I hate to wrap bodies in sheets of plastic.
Amazon:
https://www.amazon.com/gp/product/B008Y4FSTM/?tag=wranglerorg-20
This is the full set of gear to get you started. If you need more than one can, you can get just the cans for about 1/3 less from the same source on Amazon.
When I get the brackets (L&R) worked out and fabbed up, do you want a set? Just a Left or just a Right? It's as cheap to fab up a dozen as it is to fab up one. The money is in the setup time. They would be a really simple bent sheet metal part out of probably less than 10 gauge. The gas can mounts are really pretty cheap on Amazon as well. Probably $25 or so, unless you have a buddy with one hanging around under a workbench or something. I intend to make them sturdy and easily removable. Pop them in when you need to, or leave them out most of the time.