Many of us on this site live overseas, and are aware of horrific US postal charges. I gave up buying pretty well anything photographic from the USA about seven years ago as the OzBuck was so low, the ridiculous exchange rate made paying for good(ie)s in US$ uneconomical for me. As I write it's about US$.73/A$1 and going by Ebay postage charges to ship gear across the Pacific the US PO seems to be indulging in highway robbery, so I won't be buying any Thornton formulated soups from TPF.
As I now run a minimalist darkroom, I have shifted to mostly compounding my own B&W film and print developers and a few other more specialised brews with scales and bulk chemicals and I nowadays buy only fixer and C41 or E6 Tetenal kits in liquid form. Bulk chems can be purchased at quite reasonable prices from an outfit called Vanbar Photographics over in Melbourne and so far shipping has not been too expensive. (Film prices in AUS are too high and I now buy in bulk orders from several Asian suppliers.) Home brewing the Thornton two bath, Stoeckler's and Beutler's developers is easy and quite cheap, also Kodak's D76, D72 and D52. Greater availability of older types of emulsions from suppliers such as Adox, Rollei, Ferrania etc means in the not too distant future I will get renew old acquaintances with a few of the fine old 1920s developers many Old Timers in the photo trade were using in the 1960s when I first got interested in the darkroom, so it seems one wheel in the photo industry has come round to a full circle. Like Ian Grant, I kept detailed notebooks with formulas, tests and even sample negatives from various films, over the past decades and I look forward to getting into those ancient notes again.
Indeed, as one poster has noted, mixing one's own from raw chemicals isn't for everyone. Many sources for the few chemicals needed for the Thornton's two bath mixes can be found almost anywhere, not only from photo suppliers. Old Kodak chemicals turn up regularly in garage sales or secondhand shops in Australia, and I've not yet bought any that were too old to be used, except one batch of ancient glycin that had turned black, and that was given free to me anyway. One bottle of almost prehistoric potassium bromide in my chemical box is dated 1917. I used some for a D76 mix I made about a year ago and it worked, at least I think it did. Results were OK, but that may have been just luck.
At the very least, I can go to ground and make two pots of my favorite Arabica blend at breakfast time, one for me and the other for my Jobo system...
My thanks to all posters who have passed on some very useful information in this thread.