So, just today as I was driving, the ABS light came on.
I checked the fuses and they are fine.
What all can cause the ABS to stop working?
Its not just the light because I can now lock up the tires, and the pedal doesn’t try to rattle my leg off. Could this be a cheap fix, or should I bring it into a shop?
There is a section under teg tips that deals with this problem… There is a little computer by the back seat (coupe) or trunk (4 dr) that will tell you what the problem is. Check teg tips 
check the brake fluid level in the abs resevoir
Make sure your parking brake isn’t engaged. Go around to each wheel and make sure that the sensor for the ABS doesn’t have anything on it. The sensor is basically a magnet. Make sure you’ve not ran over some metallic crap and its interferring with the reading.