I live in Florida and a local bar does a gimmic where if you flip a coin and it comes up heads your shot is free. Tails, and the shot is normal price.
Is this legal? And if so, why?
"Flip Night" is a traditional bar promotion.
It is quasi legal, and may be subject alcohol beverage regulations.
It depends on if nothing is risked by the patron, it isn't really gambling, just a gimmic.
Here is an example (the heads tails, call it doesn't matter...)
If the Bar is playing it like
Heads= Free drink
Tails= Pay for your drink and get your shot
That isn't gambling, since there was no risk.
IF this is the bars game:
Heads = Free drink
Tails = No Drink and You Pay
That is gambling...
Let's put it this way, if the agency that regulates licensed premises for the sale of alcohol has a problem with it, they will put an end to it.
If you believe they don't know about it, go ahead and complain.
If it is legal or regulated, I would strongly suspect it would be because of rules about giving away alcohol or discounting fixed prices, which is expressly forbidden is some states. I don't know in Florida, but I am sure the rulebook is readily available online.