work (one's) way through
1. To stay engaged in a task continuously. Often used when the task is long-term or plodding. We're working our way through the set of problems the math teachers assigned I have to work my way through any book I start, even if I don't like it very much.
2. To work in order to pay for some long-term educational program. Kate is working her way through college, but it's taken a while, as she's only been able to attend classes part-time. You don't even realize how well off you are. When I was your age, I had to work my way through school!