In the UK you can get it from most chemists.

I sometimes carry some. A little goes a long way, so the trick is to find a quality container small enough.

I might carry it more often, but for me its most valuable if you also have glycerine and glycerine is even harder to store - it seems to leak out of most bottles unless they are very well sealed. I kinda lose my nerve over the fire risk if leaking glycerine gets to the crystals. There are more reliable fire-starters anyway, especially in cold weather.