When I bought my 190E the front door locks didn't work. The trunk lock was the only one that would lock and unlock the car. So I just used the trunk lock all the time.
But then, while parked at Assateague, I tried to unlock the car and I felt a snap (transferred through the key) and I was locked out (no locks working). Luckily, it was at the beach so I had the windows partially down. With a half an hour or so of effort, I was able to get into the car, but I can no longer lock it. I visually inspected the driver's door lock and the trunk lock. They both have obvious physical breaks in their workings.

So I'm looking at replacing the door locks and the trunk lock, but how does that work with the key? Do they all come with new keys? Are they keyed the same as the original somehow? Is there a key cylinder that I will switch to the new locks so keying doesn't change?

Also, where is a good place to get these, and about how much should I be expecting to pay?

Thanks.
-Brett