Another option is to purchase the educational version and then download the free retail software direct from Lego
at this link. The main difference is that the edu version seems to have a lot of tutorials that the retail version does not. But that's the version of the software you would get if you purchase at the store, anyway.
I was trying to by a set last summer at this time, and they were out-of-stock everyplace then as well. I wonder how many they produce each year, and if it is tied to need to supply 20,000 FLL teams at the beginning of August?
It is pretty ridiculous that people are asking $500+ for them, though.