What should I do about my broken sewer line?

In the long run it's better to replace the whole thing, cause if it broke in one spot, it's just a matter of time before the rest goes.....So if I were you I would have it replaced....If you are low on money you can save money by doing it yourself....The hardest part is digging it out, so you can save money by digging it out and having the plumber do the rest or just do the whole thing yourself, and just spend money on materials. Just buy some ABS pipe, most likely 3" or 4" pipe and the no-hub fittings (clamps that have rubber on it) to connect the ABS to the cast iron, and the glue to connect the pipes with....Just make sure there's a slight slope to it.....It is possible for you to do it to save a lot of money!!!