River Ave. Blues presents Yankees ticket prices adjusted for inflation:

A funny thing happens on the way to 2008. It now appears as though ticket prices for the Yankees remained steady, in 2008 dollars, for nearly thirty seasons. In 1967, it cost $3.50 to purchase a Yankee field box seat. That's $22.18 in 2008 dollars. Twenty four years later, in 1994, it cost $17 to purchase the same ticket or $24.28 in 2008 dollars. In 1994, $3.50 from 1967 would get you $15.53. Ticket prices, in other words, were tracking inflation.

The spike -- and we seem to still be in the middle of it -- occurred following the 1994 season when ticket prices went through the roof. All of a sudden, the Yankees were good, the Yankees were popular, and the Yankees were very, very expensive. In 14 years, Yankee ticket prices have increased by a factor of 10 from a 2008 value of $24.28 in 1994 to $250 in 2008. That's crazy.

There was also a lot of wealth created in the New York area during that time. As long as the place keeps selling out, expect the prices to keep rising.