POS & Direct Mail

What does everyone do with their POS data?

I have a POS system for 5 months now… and just started doing a 30 day lazy customer mailing. Does anyone mail first class or bulk rate. Its look like it can get pretty expensive doing 300 pieces (costing $72) a month. I have no clue what to do as far as getting a permit, dropping off mailings, etc. and if its worth it to save money. Any help would be greatly appreciated!