I've had a couple of occasions this year when I've had to scrounge coffee money off colleagues at work, after accidentally giving all my change to a homeless girl with a dog that I stopped to talk to the previous night. Buying coffee for people would seem like the ideal way to cut out the middleman.

On the other hand, my little gang of Big Issue sellers took good care of me from time to time when I was in Edinburgh so I always try to pay that one forward in whatever way I can.