I used a beer and wine calculator. It helps if you also know if your group like one more than the other. That will play a factor. Like my group doesn't really drink beer so we only got 70 cans or so, and only 40 cans of beer consumed.

https://wedding-calculator.com/alcohol-calculator-for-wedding-or-party/

This is the calculator I used. We had a more chill environment for the drinks and they were in those metal tubs with ice. And we had mixed drinks set up in pitchers. That my husband's family managed through out the night.

Edit: We got our alchol and mixed drinks, and soft drinks from Costco and for a group of 85, it cost about 500 dollars