Doughnuts and Halloween questions!

Just look in your build menu

But which ones are going to be prizes and that do not need to be bought XD

The only thing in the build menu that will be a prize is the Indian Burial Ground. Everything else must be bought.

There's multiple threads about this, including the monster thread "TSTO Halloween Keys to Success (Updated with Answer to Trivia Question)" in this forum @ http://forum.ea.com/eaforum/posts/list/9732119.page
And the stickied walkthrough over on the FAQs & Walkthrough section.