You can find free parking in San Francisco, but for how long and where? The residential permit areas are two hours on weekdays (and some on Saturdays) unless you have a valid residential permit. There are actually residential parking spaces near Fishermans Wharf, but what good will they do for a tourist? Golden Gate Park has 3 or 4 hour free parking. The streets surrounding Golden Gate Park have no theoretical limit other than the standard 72 hours, but on weekdays they turn into no stopping zones during commute hours. The parking on Sloat Ave by San Francisco Zoo is free, but that's a long way from any other tourist spots other than Ocean Beach. You could certainly take public transportation from there, but it's going to eat up a lot of time. A lot of residential neighborhoods away from touristy areas have free all-day parking, but who is going to do that?
So they're charging for parking in Vegas now? What has the world come to? I looked it up, and MGM isn't charging for parking at Circus Circus. I've been to downtown Las Vegas, and the garages at the casinos charged for parking but with something like 4 hour validation at a restaurant.