If you have no knowledge about this stuff, and dont know anyone that does, start looking on Craigslist. Service call is going to cost more than a new fridge, and that's just to troubleshoot the problem. Could be a bad capacitor, could be a dead compressor, could be a bunch of things, but if you can't diagnose it yourself, you're going to pay through the nose to get it fixed.
If it's a new fridge under warranty, you might still be on the hook for labour, even if the parts are covered. If it's a compressor you're going to pay at least 2 hours labour, so it would make sense to be aware of the terms ahead of time.