My A/C turns on and blows fine but its hot. Tried freon, says it's full and its still blowing hot air. How expensive is this fix and whats the issue

You need to determine if the compressor is coming on when you activate the A/C. My guess is that it likely isn't. This could be caused by a malfunctioning pressure switch, magnetic clutch or a wiring issue among others. It is pretty straight forward to diagnose if you would like us to look at the car.