This is something we're considering. In a year or so I will have two children under 3, and DH's transport will probably have died an honorable death of old age. That will leave us with one reliable car. We could buy another, or DH could use the car for work during the week and I could get a bus pass. The financial savings would be considerable if I took the bus - we worked out a saving of £1500 a year while the children are under 5 years old and travel for free. We live in a large town with a multitude of buses, and everywhere I go is near a bus stop.
So - logically, and financially, it seems the thing to do. We could save some of that money towards a better car for when the children are older, and put the rest towards something sensible (like doing up the house we will need to purchase this year!). What is it really like though, using a bus with young children? I think I'd wait until DC2 was 3 months old before giving up the car (and I think DH's transport will last until then, hopefully), but I'd initially have a baby and a 2 year old. Will it be hell?