Not so common these days and for me personally a shame as was always a good source of freebies in that respect, I had to buy some a while back and ironically the quality of bands the post office use are pretty darn good compared to the ones I purchased (which all turned to crud after a few years and kinda dried out for want of a better way of explaining how they went).
The kids clear them up here. In my case I spent several years carrying a scooter with about 3kg of the things on the main pole back from school every day.