Oh, one more thing - if I'm going to buy anything on this site, I'll need to know who is behind it (to figure out if this is not a scam), and also - what rights do I buy. Can I change the sources a little bit and put them back into the app store?
totally agree. copyright ownership is often overlooked, yet is incredibly important. buying a copy does not mean you buy the underlying rights. moreover, even if you buy some type of implied rights, what rights exactly have you bought? presumably (but not necessarily), you can modify, compile, and publish. can you buy the source code, then turn around and put the source code in the same store for half price? what about confidentiality? can you give the code to your employee? to your third party independent contractor developer? can you give it to your friend? can you put the code on your website for all to see? it's not clear to me what rights the site is selling.