Stick- must have rudder control- twist types are the least expensive rudder, pedals more useful- but more expensive.
BEFORE you start, I recommend that you Download the game and learn to fly while playing offline.
Once you have conquered the art of flight, do some Situation Awareness exercises. Pick a spot on the ground like a specific hangar, and learn to manuver your plane through rolls and turns keeping track of your hangar. These are basic skillz you can learn offline. Then when you start your 2 weeks free trial, you can see how you fare against live flyers. Otherwise you will likely use your 2free weeks just learning to fly.