If you subscribe to roadside assistance service like AAA or OnStar, you can call them first.
You can call the police, who may take a while to get there but will unlock your car for free.
You can try any of a number of "DIY Tricks" floating around YouTube (search "unlock your car") - including the old wire coat hanger trick.
You can call a car locksmith (any locksmith with a mobile truck that specializes in autos)
Dedicated roadside assistance or a well-known local locksmith might be your safest bets if you're concerned about locks or other hardware getting broken in the process.