Cheeseman got a nicked air line out in California and I happened to have one of these fancy in-line splices. Took him just a minute to get fixed up. I got that one through Wabfab for $20. That seemed steep at the time and it is, but it worked and so I didn't shop around back when I was scrambling to finish Rubithon packing.
But ARB does make a cheaper alternative. ARB P/N 170206 is just the quick splice, usually about $10~$12 or ARB P/N ASK001 is a splice, a ferrule and 6' of hose. That's usually about $25~$30.
Still looking for a cheaper version of the ARB part, since ARB often just repackages other stuff. Like their switches are just Carling and you can often find them sans the ARB labels for quite a bit less. But in my experience, $10 probably isn't gonna be a ton more (probably about twice) than the similar product from Parker, Camozzi, Festo, SMC or whoever. The main problem is that ARB I think uses 5mm tubing and that's sort of an odd size. Wondering if 3/16" fittings would work.