The sf means "square foot", which is a weird way of pricing somewhere.

http://www.rightmove.co.uk/property-to-rent/Hackney.html#/pr...

This flat in hackney is £675 per week and is 1700 square feet. (That's £2925 per month, or $4678 per month).

That price does not include council tax or utilities. Council tax at the lowest but full rate is £864.96 per month. That's roughly $1385 per month.

Compared to the worst neighborhoods in London? Because the Mission is one of the worst neighborhoods in SF.

Also, please note the /sf (per square foot) of his price quote. I also thought it was way too cheap even for the Mission in SF, until I noticed the /sf.