Fred was having a party and was responsible for buying canned soda.  He figured every guest would drink 2 sodas and he was inviting 15 people to the party.  The local store had a deal on sodas that week.  Every 6 pack of canned sodas was on sale for $3.00.  How much would it cost Fred to buy enough sodas for every guest to have 2 cans?
Please reason step by step, and put your final answer within \boxed{}.
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