It's not also so much the rebuild itself, it is the install. I don't know if all the Focus's are the same. But a lift comes in handy when having to access the alternator, plus putting the belt back on.
On 10/2010 at roughly 50K. I had to replace mine plus parts. The alternator, idler pulley, and pulley was $345. My Mechanic does not go to Autozone, I am pretty sure he buys from NAPA with the exception of Ford only if necessary.
What I do know, is the parts are of good quality, I never have to go back and have it done again unless it is a defect within the car. And doing my research, the 07 Focus has a less than reliable electrical system.
At any rate, it cost me a painful $500 to replace it. Unfortunately with today's cars. They may be built better, but some us do not have the capacity or resources to fix them ourselves.
Let no debt remain outstanding, except the continuing debt to love one another, for he who loves his fellowman has fulfilled the law. Romans 13:8