How do locksmith businesses handle vehicle key pricing with hundreds of SKUs? What's your quoting strategy?

This is a very niche issue you're having, I can't think of any other trade that would have that many different sale items to offer to a customer. Most of us I would say are selling 5-10 services and maybe the same amount of sellable items.

The only thing that comes to mind would be to find a price that would average out your sales. If one key costs $300 and another is $100, could you not just sell both to a client for $200? This would take a lot of backend work to find a good average price, but with this issue that is the only thing that comes to mind.