I notice all these $20 an hour jobs coming over the Twitter feed on a Mission District search. Indeed, if you look at Craigslist, it does seem that if you are paying less than $20 an hour, you might have difficulty getting someone to apply to your listing.
There is this listing for bike messengers from postmates.
Healthright is paying $18.26 to $21.63.
Cleaning will get you $22 an hour.
Oops, Twice, the on-line consignment shop for vintage clothing appears to be offering only $11 an hour.