Scenery in x-plane can often be done for free. There’s free HD mesh to improve terrain fidelity, and you can often find orthophoto as well (or make your own). Other packages for airports and the like are plentiful on the org site.
If you’re looking to buy those, the carenado models go for like $30 or so each, though they do occasionally go on sale. Bigger planes tend to equal bigger cost, as well, varying from around $50 to $85 USD most of the time.
There’s a Citation X but it was made for x-plane 9 - no idea how great that is in 10, let alone 11. I haven’t watched any of the 11 release videos (which is terrible of me really), so I have no idea if they list a new default aircraft listing or not. Beach might know.
And since I noticed the ASK-21 glider there: Does X-plane have proper thermals modeling below cumulus clouds and the like? What about winch starts? So in essence: Is it possible to fly a glider semi-realistic in X-Plane? FSX sucked in that regard. Addons made it halfway decent but still quite bad.
I don’t think that the Steam sale counts toward the key for XP11, but don’t quote me on that.
No - most of my X-Plane videos contain either free or payware add-ons and scenery. Almost all of my terrain mesh is freeware (or dontationware as it were) from AlpilotX: HERE
There are literally hundreds of free aircraft you can also use from the X-Plane.org - some are really good, some are OK, and many are horrible. Some are payware quality that were released as freeware. And the stock aircraft are actually not too bad - I like the Stinson, the Columbia 400, and the P180 Avanti the best probably. According to what I’ve seen and heard, X-Plane 11 (to be released any day) will have significantly better aircraft. Not sure about the scenery for XP11…but I also read that the AlpilotX mesh should work fine with XP11 too.