Washington is a huge state in the USA. Nobody that is an auto mechanic is going to have a domain name that makes it sound like they service the whole state.
Washington DC, is a part of Maryland and Virginia, but they would like use something DC related.
Regardless, mechanics would probably have their shop/store in their name. Also, not many auto repair shops care about websites as they cater to local customers. Custom, classic, specialized mechanics might have sites, but their specialty is usually in their name.
So, I'm thinking low to mid $xxx.