It's a weird thing tbh when most of my mail is literally just advertisements for services around my area. Some of it is interesting but most don't apply to me (ex. Had several mailers for private schooling since there's a couple schools like that in the neighborhood) so I have to wonder how successful is junk mail like that in producing a profitable result. I have to imagine the cost would have to be very low to justify the constant stream of junk mail I receive.