i have a key stuck in a car door?

Go ahead and find a locksmith with a store front or walk in location. You'll would need to take both peaces to one to get a copy of a working key anyway. May not cost as much as you think not having to pay for a service call. They can look at it and tell you the cost. Walk away if you don't like it.

Turn the key around in the lock with a pocket knife to its position of pullout. And remove it by gluing an ordinary paper clip to the key with Instant Set Epoxy purchased at Lowes. This is commonly used to remove car and house keys that broke off in the locks and works very well.

Depends on what is causing it to be stuck. You can try putting it in the freezer. Perhaps the cold will cause enough contraction to get it to free up.

You can also try spraying graphite into it if there is any room to get any inside.

depends on the kind of lock assembly you have you should be able to take apart the lock assembly

try a paper clip it worked for me once