do you get cash from scratch?

No you do not get cash, everything on it is shared under the Creative Commons license (or CC), and everything under it is free for people to use and remix. Because of that, everything on this site is free, or else it would violate the CC, though there is a small way to make some.

If you make a project in the offline editor, somehow get it to a .exe file (probably through a mod), and never share it online, then your project isn't under the CC. Therefore, you can sell it as you want, though you cannot sell Scratch, or add on extra price if you do include Scratch. There was a good post on this by Sci, but I don't exactly remember where it is.

With regards,

ErnieParke

This explains how you can sell your project.