Paying to write someone (ie, physical mail) was the standard for all communication before we had widespread telefax/internet messaging adoption. I don't know how bad the spam problem was there, but the concept doesn't strike me as being necessarily awful. What's your concern?
For every legit paper mail, I've had 5-10 garbage leaflet advertisements shoved into my mailbox by half-legally working teenagers earning $1-2/h in exchange for everyone's annoyance. 99% of these went into trash immediately without looking.
