When I was young and broke I would do so many creative things with the free transfer lol. Most subway lines have a comparable bus line so I'd take the 1 to the grocery store and then the M104 back, for instance. That way I'd only pay one fare. I had a bunch of poor friends do this as well. I still try to take advantage if I end a doctor's appointment early or something by taking the alternative form of transit since you have 2h30m. It's good fun and can really work in your favor.