> overpriced lock they conveniently have for sale and in stock in their vehicle

I object to the word overpriced in this context. It costs a lot of money to keep locks, tools, and other spare parts in a vehicle (including the cost of the vehicle). If you need a lock now and they have one it should cost a lot more than if you need a lock in 6 months and can wait for the factory to get around to making it. When you call their locks overpriced you are failing to understand the costs and value of having a part on hand.