Gaw- im not sure how familiar you are with the transportation system in yerushalayim, but the bus isnt an occasional expenditure, its a neccesity for daily life, and, as such, cant be compared to a big mac. Boycotts will not work because there is simply no alternative- its not like refusing to by a braun- its like telling you not to shave ever again! (my apologies if you have a beard-you still get the point)
Way back when, I used to use my feet to go from place to place (I still do sometimes). Unless they are going to the Mall (which real Charaidim don’t go to), and assuming there is food shopping in all neighborhoods (which there is), then a boycott is a viable alternative. It’s not as if they need the bus to get to work, and there is the “Mir” bus for those who need to get to Kollel.