There are some things you can do before you call however. They seem simple, but sometimes doing some simple things can save you money.
Sometimes your steering wheel locks into place. Simply jiggle it back and forth while attempting light turns on your key to get it to unlock. This can solve the issue many times.
(by the way, make sure your parking brake is on or your foot is on the brake so that you don't happen to move the vehicle while trying to unlock the steering wheel. )
In many automatic transmission vehicles, the key isn't supposed to move unless the car is in neutral or park. Try moving the gear shift back and forth a bit to see if it releases your ignition. It is possible it just didn't recognize the vehicle was in park or neutral.
You may have a bent or worn out key. If this is the issue, you may need to get a new one made, perhaps from a spare that is in good condition, or if all else fails, you can go to a dealer and have them make a key for your specific car from their database.
The key cylinder, also described as the ignition cylinder, could have an obstruction, like a partially broken key or something a baby stuck in there, (it happens) and you need to clear that out before the key can get in all the way. You'll need to take a flashlight and look for what is obstructing your key entry. Sometimes you'll see little pieces of metal there. Either way, before trying to clear the area, wear safety glasses. You don't want a shard of metal coming out and getting stuck in your eye. That would be a much worse problem.
You can use compressed air in a can or some other device or an electrical cleaner to try and remove the obstruction.
Sometimes, it is an issue of springs and pins inside the cylinder that help form the key to the ignition and allow it to start. These can get stuck or not quite "pop" back into the proper place. It will need some small vibrations from a little bit of force to get them to "pop" back into place. You can use a small tack hammer or skinny headed rubber mallett to do this with. You don't want to hit it hard, or you may do more damage to the ignition cylinder. You just want to apply enough force to cause some vibrations to set the pins back in place.
If you have tried all of these things and you are still having issues, you'll need a service professional to look at it and get it working again. If you go in to deep without proper knowledge and tools, you may end up costing yourself more. Let us help you trouble shoot and if necessary, tow your car to the right place if we can't get you up and running. Please call Towing San Antonio at 210-390-1181