Is this a baby or has it had more then one home? I think you would be better off with a baby if you have no experience with Amazons. As older birds that are rehomed tend to have major behavior problems and a hard bite to go with it. Just be sure you know what your getting into before you make that choice.
You want the biggest cage your wallet will allow. The first cage would be fine and could be just a bit bigger the second cage would be fine but you have to have alot of room.
Good luck on your baby and what a great way to start off a new year.