Yankees 15 game season ticket package?

Around this time last year my mom was trying to do a Yankees 15 game season ticket package for me for Christmas. Next year my friend wants to get 4 tickets in the bleachers for 15 games or so. I pay for 1 ticket and he and his dad will pay for the rest. Anyone know how to find this on yankees.com? I did this with my family for the 2008 season.