I can't get the key to turn in the ignition.

I've tried the turning steering wheel trick, hitting the key in the ignition(which worked for a few months after it started happenening but won't work now). We have a warranty on the car and if we take it to a locksmith the warranty will be voided. We can't get the car in neutral because the key won't turn and unlock the steering wheel, and the gear thingy. What can we do to get it to work. We can't afford to take it anywhere because I am currently out of work and my husband JUST started a new job and won't be payed for a while.