Hi Jo,
Your liquor licensing authority, your business licensing authority, would be the two main places to ask those questions. They will be able to advise on the applicable regulations regarding holding such a tournament.
As for the cover charges, it will depend on where the money goes. If it is all kept by the bar, I'd guess you could charge anything you like. Just a matter of whether people are willing to pay it. If you are pooling the fees for prize money, you might have gambling issues. That would be your local district attorney's office.
Hope this helps.
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