@Lorna170 Yes, sometimes it's possible to extract the broken part from the lock yourself. Then it's just a matter of getting another key cut from your spare, which costs what, a few bucks?
I have 4 sets of keys for all my doors- one I carry with me in my bag, one stays in the house, one is hidden outside in case I lock myself out, and one is for guests (that set just has the key to their door, which has an outside entrance, and the key to the kitchen/living area, not my bedroom or my storeroom).
My locks are deadbolt types and can be easily changed out by undoing 6 screws, which is much cheaper than calling a locksmith. I had a housesitter who had a key get stuck in the lock (not her fault, she took excellent care of my house). She was a very capable gal, a home owner herself, and just went out and bought another lock and replaced it herself.