There are unlimited supplies of Jack's Magic in our local GC!
Like others here, I'll be stocking up for several years' use! The good thing about such good quality compost, is that you can use it time and time again, just by adding a few nutrients and a bit of the stuff from the compost heap!
I have some big pots with Jack's Magic or other good peat-based composts which were filled several years ago, and, by doing the above, have never have a problem! Growing toms, peppers, etc., in big pots and trays does mean that at the end of the season, there are quite a few tangled roots to deal with, so all I do is chuck them together in a dedicated home compost heap, and they'll rot down normally!
Recycling compost - the good stuff, with plenty of peat - is dead easy, and saves a fortune in the long run!