what you can afford, being number 1 priority
vs if you have played this game in H2H mode for any length of time and think you will stay here for awhile then I would suggest either
CH Products ( fighter or combat stick with Pro Throttle and Pro Rudders - ie.... complete HOTAS setup )
or
SAITEK X52 or X52 Pro - Stick / Throttle / Pedals.....
you can also start by buying say just the CH Fighter Stick and Pedals, then add the throttle later ( Stick has rotary throttle on base U can use )
if you just want to test the waters, you can get a SAITEK EVO or ST290 , or even a Logitech Extreme all these are fairly cheap......
Ren and other Trainers have listed numerous times in numerous threads what minimal requirements in a stick , one should look for in starting out.........both in the Help & Training Forum, in this Hardware & Software forum.....
just use the Search function of this Messageboard and type in "Joystick requirements"......you will find many thread topics on this subject........
good luck......