I just bought my first Focus not long ago. If you are getting it at a fair price and the vehicle seems to be well taken care of you should not have much to worry about. I have found these cars to be very simple to work on compared to other vehicles I have owned and the cost of parts seems to be fairly cheap for everything I have bought so far.
I am in the ATL area, after you get it if you ever want to meet up let me know. I am up for meeting other members and talking cars sometime.