I know this is a bit off-topic, but does the MTA's SIRT still provide largely free rides? For those who don't know what I'm talking about, the Staten Island Rapid Transit service is a one-line metro serving Staten Island (duh!). But fares are collected at only one station (St. George, at the north end of the line), from passengers both boarding and disembarking. Passengers coming from or going to the Staten Island ferry (which is also free) who don't want to pay to ride the SIRT can walk to or from the next station, Tompkinsville, and ride for free. To discourage this, some trains, especially during rush hour, don't stop at Tomkinsville or any other stations between New Dorp and St. George. I don't know how long of a walk this entails, but it was my understanding that something like less than 20% of operating costs were recovered through farebox revenue on the SIRT--though lost fares would also of necessity include any and all trips originating and ending at stations other than St. George.
I believe there are (or were) also some free-transfer offers for passengers traveling to or from Manhattan.