Question: We have quite a few [questions on tipping in the USA](https://travel.stackexchange.com/questions/tagged/tipping+usa), but looking through I can't seem to spot one that covers this.

When in the USA, if you are somewhere where drinks are free but served to you, is it expected to tip the person pouring / bringing the drink, and if so, how much?

Additionally, does it vary by location / setting? For example, might an airport / hotel lounge differ from an all-inclusive hotel / resort?

(I'm currently in an airline lounge at a US airport, and was given some vouchers for free drinks when I entered, which are given to the barstaff in exchange for drinks. Some people seem to give a tip, some not. A few weeks ago I was in a hotel lounge which had free drinks for an hour in the evening, with a member of staff removing beers from the fridge and opening them for you, but I was the only one there then so didn't have anyone to copy....)

Answer: 
In general, if you're in a place that also *sells* drinks and you're using vouchers, etc then tip as you would if you'd paid. So a dollar or two per drink depending on price and place. Same goes for discounts and other freebies like a 2 for 1 deal -- although you could choose to tip more up front. Obviously if the staff just decide to give you a freebie then tip on that too and generously (since you just got a free drink). 

Otherwise, if the staff rely on tips, they lose out because someone has scored some vouchers or something. 

For all-inclusive, I'd follow the same rules as you would at a similar non-inclusive resort in the same country. Unless it explicitly says somewhere that tips are not expected / are included. 

In the free hour at the hotel lounge it's more tricky. Again if it's a normal bar and a bartender then tip as normal (or tip all at once up front or at the end). If it's just a hotel employee occasionally fetching you a drink I wouldn't think tipping is expected. But it's probably appreciated so maybe leave them something at the end of the hour.
Tipping in North America has become such a hot button issue. It is customary to tip and is usually a percentage of the cost of your food/drinks (or what the cost would have been). But there have been so much writing happening on this topic like:

1. Why is the tip calculated on post tax amount and it should be pre tax which is just the cost of food/drinks (delivery services usually do the former but you can change the amount)
2. The minimum tipping post Covid has gone from 10% to 18% (here at least in Toronto). People argue that the cost of food/drinks has itself gone up so even if the tip percentage was to stay as it was pre Covid, they are still earning more out of it. There is no need to increase the tip percentage too in addition to already now expensive food/drinks.

Although this discussion wasn’t a direct answer, majority of people would tip depending on quality of food/drinks and the kind of service received.