Not sure if anyone else is offering this service, but figured I would do an interest check before setting up shop. Books of 20x Forever Stamps. Price won't be USPS prices but won't be to much higher && best of all we would not log details/take your picture when purchasing like those pesky machines do!
You'd probably do more business selling priority and international stamps. Regular $.49 forever stamps are available for anonymous cash-purchase just about everywhere.