I'm missing the Helter Shelter from the spin wheel and I think, Homer Snowman and the Christmas Skin for Cletus' Farm. The rest is just money or gift cards. I'm not really fussed about Barney's other skin as I don't even own him in the first place, so I hope not to land on it!
I haven't spent any "real" money on the game and don't really intend to.
It would be nice if the game could adapt itself to offer gifts relevant to what each player owns. For example I only got KrustyLand to place the Twirl-n-Hurl during the Halloween event. Having said that I guess they want to encourage people to part with money and buy premium characters.