We don't quote a number here that we can't back up in FACTS, so we won't invent a price for this specific repair. What we can tell you is what drives the number up or down on a Mirrormont call: whether it's one spring or the matched pair, whether the cable and pulleys need replacing along with it, and whether the door is original enough that we're sourcing older-style hardware rather than the stock parts we carry for newer torsion systems.
Household income in the surrounding service area runs well above the regional median - $182,283 here in Mirrormont against the wider area's figure - but that doesn't change what the job costs; the parts and labor are the same whether the driveway is in Mirrormont or six miles away in Issaquah. What does change is how often an older door like this needs a return visit if only half the problem gets fixed the first time, which is why we'd rather replace both worn springs than patch one and see you again in a year.