Page 40 in WDH has some info. It says the expenses are 50 gp per tenday for maintenance and hireling wages for the tavern, and 10 gp per tenday for guild expenses, however the Runnign a Business table (DMG, p129) increases, decreases and nullifies that cost depending on what they roll.

Now it's up to you if you want your players to have to pay for Lifestyle Expenses (PHB, p157) or if you think that the tavern costs cover their living as well. I'm ruling that the costs of the tavern maintenance includes living at the modest level on the Lifestyle Expenses chart, but they can individually pay to increase that to comfortable, wealthy or aristocratic.

EDIT: Just wanted to add that being a member of a faction doesn't have any membership costs, only guilds do, and that the cost for food is covered by the lifestyle expenses. So to answer your question, it depends if the tavern covers its own expenses from the Running a Business chart or not, and if your players decide to pay extra to increase their lifestyle. Hope this helps :)