In Munich, Germany (one of the priciest cities in Germany), the overall average rental price is €700 for a one-bed apartment[0]. Compared that to London, a one-bedroom apartment rent is going to cost you over £1000! €1178.48 euros![1]
In Eastern Europe, you can have a very good quality of life for even cheaper. The only problem is the language barrier.
I live in Sofia, Bulgaria, and pay €340 euros for a 2-bedroom flat in a pretty nice area of the city. A coffee costs around 2 лв (about €1), average pint around 3.80 лв (about €2). With a London software engineering salary, I save a drastic amount of money compared to London, and can usually afford to go to more restaurants, bars and outdoor activities (Love that I can ski just 20 mins away in the mountains!)
I assume it would be similar for people who can work remotely for a San Francisco company but live in a different state?
[0] https://www.expatrio.com/living-germany/costs-living-germany...
[1] https://www.london.gov.uk/what-we-do/housing-and-land/improv...