They ask for a "free will donation" to enter the site, with $20 strongly suggested as your donation. If you donate $20 you get a bumper sticker and hat pin. The more you donate, in multiples of $20, they more they give you. If you choose not to donate, it looks like you can enter for free. I was visiting alone, so I assume the donation is per vehicle.
The field looks almost exactly the same as it was during the movie, and the same for the stands/bleachers. You can run the bases or toss a ball with your friends/family on the field.
There's a small place to purchase food/snacks near 3rd base, but it was closed around 2:30PM when I walked over there. It was open when I arrived about 45 minutes earlier. There was a sign for hours of operation, but there were no hours posted on it.
The house is available for tours (extra entrance fee) and...
