You'll probably have a decent experience if you happen to have an Xbox or PS4 controller lying around. The next step up would be a joystick (maybe $50-$300 depending on how fancy you get). If you're super hardcore you can also get a yoke and pedals, but I think that's overkill unless you want a super realistic experience
You can get a Thrustmaster TS16000M for less than $50, which is a great joystick to start flying. There are much more complex and true-to-life systems, which can cost several hundred dollars. It all depends on how much realistic you want your experience to be.
And yes, playing FSX with Xbox controller, landing is where I wish I have throttle or sometimes even rudder controller (since by default the directional control controls nose gear, ailerons, and rudders at the same time)
If you want to get a bit fancier the next step up would be something like a Logitech X56, which will give you twin throttles, several other slider/knob axes (prop/mixture controls, etc), and a lot more buttons of the stick. That's around $250.
From there you can get to pretty crazy high end stuff, some of which use real airplane hardware.
You need a stick and a throttle. I've been using Saitek X52pro which has both (HOTAS) to play Elite Dangerous with Rift since it came out and they are good but there are many other options available out in the market. For MSFS you may also want to have rudder pedals.
For folks who are aware about this, do you need to get specialized controls to enjoy the experience?