File this under one of those things most people don't know about:

Pepsi Picnic Area
Every Wednesday home game, the first 1,000 fans to arrive at Shea with an empty Pepsi can or bottle will be admitted to the Pepsi Picnic Area for free.

So, on those nice summer evenings when you have a day off and are looking for something cheap to do you can actually get in to see the Mets for free if you get out there early enough (or close enough to free if you bring along a can of Pepsi).