Every year, the Team Marketing Report calculates their "Fan Cost Index", calculated as the total of:
two adult tickets at the average price, two child tickets at the average if available, two beers, four soft drinks, four hot dogs, parking, two programs and two adult caps.
Here are this year's calculations; TMR says the average has gone up 10.9%, the largest increase since 2001. The Red Sox have the highest average ticket cost, $48.80. The Cubs are second at $42.49, up 23%, and if they draw approximately what they did last year -- 3,252,462 -- which seems likely, that would generate over $138 million in gross ticket revenues. (Theoretically, this should allow them room to go out and acquire/buy a player later this summer if needed. Theoretically.)
This approach is a bit simplistic. First, according to this ESPN article on the topic, the Yankees really have the highest average:
Jon Greenberg, TMR's executive editor, said the team did not provide data and that he did not include the price of premium seating -- which covers a large percentage of New York's tickets. Yankees' box seats near the infield had a list price of $250 this year.
Also, of the $191.75 Fan Cost Index, probably 1/3 of it is accounted for by the caps and programs -- and not everyone buys those. The "real" Cost Index, then, is probably closer to $140 for a family of four.