A few of my favorite tricks to beat the MTA out of an extra $2.25 includes taking advantage of the 2 hr free transfer provision:
If you take the subway one way, and want to go back to where ever you came from, take the bus instead and get a free transfer.
If you hop out of the subway in midtown and walk around for a bit, you can re-enter the subway using the 2 hr free transfer at either the 59th/Lex (4,5,6,N,Q,R) or 63rd/Lex (F) stations, because those two stations feature an out of station transfer.
Sure, you're not getting rich on either of these ideas, but every little bit helps!
