Key coding tech is getting much cheaper these days which is helping put it in the hands of more and more lock smiths and auto electricians.
Essentially to program these keys, you need to plug in to the car tell the car you want to program new keys, then put each key one by one into the car then confirm at this point the all the keys are accepted into the system, and keys previously programmed but not inserted during programming are locked out securing the car against any lost keys, it takes time, the keys are cheap the tech is fairly cheap (though out of the realms of the home hobbyist) so the price they quoted you is vastly inflated I would asking for a break down of what you're actually paying for
