You know, without actually stealing it.
This is, apparently, the difference between the two.
Manga Studio 5 (which for previous versions was known as the Debut version) is much cheaper, but has fewer features, while Manga Studio EX 5 has the full range of software features at a higher price Manga Studio EX 5's main difference from[...]
manga studio 5 Archives
It's not just for manga. The PC and Mac program loved by comic creators worldwide is currently down to $17.99 on Amazon as opposed to the usual $79.99