I make many FOIA requests as part of my law practice. And I've noticed a troubling trend lately--some agencies (and no, I won't name them publicly) don't use the United States Postal Service to send out responses, they use Fedex or another delivery service. And this isn't for just FOIA releases, it is for routine letters. The cost of a letter sent through the post office is $.42, the cost of another delivery service is at least $5.00. Multiply that in the hundreds and you are talking real cash.
As a taxpayer, I just don't understand why these agencies can't just use the postal service and also, if they are worrying about timeliness, send a pdf via e-mail. It would save us all alot of money (that we don't even have in the first place).