Mobile Post Offices
Shortly after getting my first apartment, I was like a lot of fresh out of college kids always forgetting things like postage stamps. One day, when I had to mail an already late payment, I simply taped a quarter and penny or two to the envelope. I figured the post office would know what to do. As fate would have it, the apartment complex's postman happened to be delivering mail to all the boxes. While he wasn't too pleased at my solution, he did offer me an alternative.
http://www.stamp-co.com/stamp_collecting_blog/trackback.cfm?2B787C6A-3048-293E-AE62EFBE9952B660

I'm researching to find the value of these stamps, if any. Any information on this would be appreciated.