Chris Jaffe at The Hardball Times on baseball ticketing fees, processing charges, and so forth. Here's what he told me via e-mail w/r/t the Mets:
Among other things, the Mets are the only team in baseball that charge you money to mail tickets to you when you buy them online. All others do it for free but the Mets charge $4. In fact, all methods of delivery cost money from the Mets - online printing, UPS, and mail. They're currently the only team to lack a free way to get tickets purchased online directly into your hands (and I didn't see a leave at will call option for them). As a result, the Mets have some of the highest overall add-on fees in MLB.