A beverage-service system where the host provides and pays for all of the drinks (i.e. free for guests) is known as an open bar.

open-bar-sign

The opposite of an open bar is a cash bar.

Merriam-Webster Online Dictionary
open bar (noun)
a bar (as at a wedding reception) at which drinks are served free - compare cash bar
Synonyms:
Hosted Bar
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About the Author Debbie Quain

I created and hosted Weddings for a Living between 2010 and 2016 as a space for honest conversations about building a sustainable company of one in the wedding industry. While I'm no longer recording new episodes, I'm still cheering on solopreneurs. Find me on Debbieville.com. 💛

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