The only thing better does not yet exist
Having a stick will improve the game significantly over keyboard. I wouldn't hesitate to buy one.
A nice cheap stick to get you started would probably be a Logitech attack3 ($20) or attack3-d ($30) with a twist-stick for rudder. I've had mine for years without problems, but I've heard horror stories, so beware.
My current stick is the Saitek AV8R. It's $40, but I got mine from a friend. Even used, it works flawlessly, and is practically guaranteed to last years and I've only had to calibrate it a few times in the six months that I've had it. It's got two levers, twist, and a hat-switch. You can't go wrong with this one.