Answer:
DUH.. Obviously. there's a bunch of ticket booths at the Amusement Park entrance, and you can easily walk up to it and buy tickets there. Everyone does it... so I don't see why you couldn't. I wouldn't recommend buying tickets online unless you are absolutely sure you're going on that particular date. These tickets will never run out, so buying them online is pointless unless you want the entire vacation package (including hotel accommodations, etc).
>>>Yes you can buy them at the entrance. As you can see I was nice in my answer unlike the person above! HOW RUDE!!