AP's annual survey of ticket prices turns up the information that the A's are 24th out of the the 30 teams in ticket cost, with an average ticket cost of $16.49.
First -- this will not knock your socks off, so to speak -- is Boston, at $40.77. That's average ticket cost.
Second is the Cubs -- $28.49, over twelve dollars a ticket behind Boston -- and third is Philadelphia. The Yankees are fourth, Seattle is fifth, and the Giants are tenth ($21.60; I'm surprised they're that low).
The team with the cheapest tix in the majors is the Washington Nationals, at $10.82, edging out the 29th-ranked Florida Marlins. Both of these teams may be benefiting from including vast numbers of cheap, third deck seats that no one will ever sit in. For that matter, the A's may be benefiting from that, too.