What could be wrong and any idea how much to fix something like that?
My car has 125600 miles.
On a vehicle that is 15 years old you may have a leak in the condenser, compressor, or evaporator. One of these faulty components may be leaking down the pressure. It’s also possible that one of the pressure switches has just stopped working. I can only recommend having a certified mechanic, like one from YourMechan, diagnose the A/C system to see what caused the issue.