What market? I kept googling Lyft driver SF and clicking the advertisement links. They auto-fill and on the Lyft landing page it tells you what the bonus is.
For example, SFOBONUS400V3L, gets you $400 in SF. I used one that got me $1,000 after 300 rides in 60 days. They are someone's referral codes, but as long as I get a bonus I'm happy with I don't care if someone else is getting the referral.