If you want to head straight south or straight north you won’t have to go further out than 1 hour before rents and property values fall significantly from city center Seattle. Tacoma is 30 minutes away without traffic and has a median home price 40% less than Seattle. Drive till you qualify is real.
If you want to head east, you’re running into the real estate aftermath of Microsoft making tens of thousands of millionaires in the 90s and 00s. You won’t save much money there.
Yeah, it varies in a lot of cities. I live about an hour (given not a lot of traffic--hah!) west of Boston and the real estate prices aren't cheap but not crazy. A lot of the tech industry was out that way anyway historically until pharma and outposts of west coast companies took over Kendall Square. But certainly a lot of the coastal towns north and south of the city are pretty pricey.
Yeah, the Eastside is a real estate hellscape. Everything east of Lake Washington till highway 203/18 is genuinely quite bad. I had cheaper rent on top of Queen Anne, 1 block from the Trader Joe's, than any place of comparable walk/transit on the east side ($2065/month for a 2 bedroom 1.75 bathroom apartment+1 parking place, ~950sq/ft).
With traffic, Tacoma isn’t very viable. Also I have a relative who commuted to his job in Tacoma from…west Seattle (granted they bought in the late 80s). It was an easy reverse commute (so close to actually 30 minutes?), going the other way is hard and you can only win with the train (sounder) or maybe bus. Link is making its way down to federal way soon (or already?) but that assumes you work near a station or it quickly becomes not competitive with driving.
My mom commuted to Redmond from Bothell when I was in high school, horrible traffic…and that was early 90s. You don’t want to do anything on 405 during rush hour.
You can also head west if you dare. I have a coworker commuting in from Vashon Island. I don’t think prices are that great on the islands though, maybe 30-20% less than Seattle, but you live by the ferry schedule and if you want something near the ferry dock you’ll pay a lot more for that walk on convenience.