I think it's in parts a very subjective question, who purchases what. There are some general things: Large Area for a cheap price, as has been mentioned like with Howdys scenerys, that's I'm sure interesting for a lot of folks, even if they don't fly the region often. That's why I bought the "virtual comumbia" package. However, for example, I purchased http://www.eiresim.com/leal.html as you know. Single airport with what I would say standard features of high quality payware at nearly the same price than other complete packages. But for the wrong simulator, so I even converted it, and of course it's not perfect. So for me, for this airport, I would be willing to pay even more for an as good as or better native xplane version. Time is money, too. Also, you might want to start with 1 or 2, later make that a package of 3-5 in a bundle. like howdy did KPAE and the surrounding area. Nice strategy. I'd say: Release one airport that you have for a really a low price, like 4.99$, and collect as much feedback on this one as you may get.