2002 Pontiac Grand Prix Key Release - Will not let go of th

2002 Pontiac Grand Prix Automatic 161000 miles

After starting the car, when shut off the car and try to remove the key, it seems to be locked in. It can take anywhere from 2 seconds to 4 hrs to get the key out. It seems the key lock is not releasing when the car is put into park and shut off. What could the problem be? And how can it be fixed? Can it be fixed without having to take it to the dealership (since it costs a fortune just for them to look at the car and we currently have no money for repairs).