Is it possible to get my 2007 Scion tC rekeyed and what I should I expect to pay

Hello, yes you could have all of the lock cylinders replaced, as well as new keys provided. The new keys will also need to be programmed to operate the vehicle. You may consider, instead, to have your key code retrieved from your local dealership (if you do not have it in your vehicle documentation) and have the dealership cut a new key for your existing locks. Although it won't prevent someone else who finds your keys from getting into your car still, but once the new keys are programmed, the old ones will not be able to start the car any longer. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops