CH FTW. I've heard the Thrustmaster Cougar's internals are poorly made and require a bunch of mods to make the Cougar useful, making the full cost several hundred dollars and up.Here's
a review comparing the CH sticks and throttle to each other.Fighterstick
(top of the line) currently on Amazon for $107, Combatstick
(fewer buttons but probably just fine for space sims) for $80, Flightstick Pro
(just 4 buttons and a hat, smaller stick) for $72, Pro Throttle
I have the Flightstick Pro and the Pro Throttle. The Flightstick Pro's number of buttons is okay for a space sim. It'd be nice if it had a few more, but it works fine if you're using it with a keyboard or a throttle. The main reason I chose the Flightstick Pro over the other two sticks was the stick size: the other two sticks are modeled after the F-16's and are probably too big for my hands. It doesn't hurt that DOSBox has built-in support for the Flightstick Pro, making it really easy to use for games like Descent.
Note that the prices for these items can fluctuate from week to week (even day to day) on Amazon, so if you're willing to wait a bit, you may be able to get a better price. That said, the Pro Throttle and Combatstick are probably at around the lower end of the price range I've seen on Amazon for those items, and the Flightstick Pro and Fighterstick at the upper end, although at the cheapest I've seen the Fighterstick, it's probably no more than say ~$10 less than it currently is.
Hope that helps.
As for used, well, I just wouldn't buy a used joystick in general (too risky), so I dunno. If you buy new, CH has an excellent reputation for customer support.
EDIT 2: A review
comparing CH Fighterstick/Throttle to x52. The link points to the CH section.