I agree, a serial number is needed. But that doesn't mean it can't be included with the disks. And, as far as I know, Adobe allows users to 'transfer' their software to others just like other developers. It's simple edit of the ownership records...and if they don't I would consider legal action against them...if you have the time, of course. At any rate, if Elements (whichever) can provide all your needs, it's
many times cheaper than the full version of Photoshop, even if you get an educator's discount!
I don't even know if you can buy PS alone...
Then, there is <
Pixelmator>($29 at the App Store, and that appears to be the only way to buy it from now on...[you might want to read some of the disgruntled users about that!]), Graphic Converter (newest version), etc. And, Elements 9 (as were earlier versions) is $79 with a $20 mail-in discount, so for a while, anyway, its total cost is $59.
44 (or whatever a first class stamp costs...). That's a moot point, however, since it requires 10.5.8 or later...