In my area, there are two LQS that service Berninas and Janome/Baby Locks. Each of them charges around $80 for general maintenance, then if anything else is needed, they will call and tell you how much it will cost to fix it.
With most machines, if you will do two things consistently, you will hopefully never have a repair issue. (1) Clean the lint out of your bobbin area EVERY TIME you change the bobbin. You will find that different threads and fabrics generate different amounts of lint. Do not try to blow lint away, as this will put moisture into the machine's innards and may cause problems down the line. I use a Q-tip, others use a brush (either the one that comes with your machine or something like a medium art paint brush) to catch the lint. (2) Oil and lube your machine every 6 months. Your manual will show where the points are. If you don't have a manual, google your machine model number plus the word manual and you will probably find one online. On my Bernina, I put a drop of oil in the bobbin area at least once a month.