Last time I looked, you could download many many upgrades, new scenery and many new planes. The one thing you should know is that you have to download and upgrade them more of less in order- you cna't install very recent scenery if you also haven't downloaded the recent simulator 'engine' (main program) upgrade.
By the way: I paid about $175 for it, so if you can get it for $39, I'd say take it- that's a great deal.
I need to check for upgrades and get my version current, too, this discussion reminds me...