No, that's illegal. Participants are playing with chips only. No side bets are allowed.

Can I get more chips if I buy food or drink?

NO! That's also illegal. Look at what Ken Peterson Chief of Investigations for the Colorado Liquor Enforcement Division had to say in a letter dated July 27, 2006:

"A card tournament must be free to the participants and there can not be any direct or indirect costs to the players. You can not award additional chips for the purchase of items such as food, alcohol. or non-alcoholic items. This constitutes charging and an indirect cost to the players. Once this happens, you are conducted a game that falls under the criminal statutes and the Liquor Code as gambling.

Gambling is a felony under liquor code and this activity would put the liquor license in grave danger of having an action taken against that license. Any administrative action taken by the Liquor Enforcement Division may result in suspension or revocation of the liquor license."