How can I purchase batting practice tickets ? Do you have a date for "autograph event" usually held before opening day?

A regular ticket will get you in for BP, autographs are first come,my wife has many. So get there early and claim a spot.

What Philip said, purchase a GA ticket get there early, the players are usually super approachable and more than willing to sign hats and shirts for kids

Check their website or call the box office.

I suggest looking at the website, for specifics