Photo Funny

Okay, help me figure this out.  These pictures were taken within about a minute of each other.  South of Market:

North of Market, catty-corner from the first one:

More than half a dollar's difference per gallon, same day, same street.  I don't think I've ever seen anything like this before.

P.S.  A sharp-eyed reader from the East Coast pointed out what I should have spotted: the sign at the bottom of the first picture, which explains $3.75 as the cash price.  The credit-card price is $4.33, almost as much as the station across the street.  If I had to drive in San Francisco, I'd be sure to have cash when I needed to fuel up.