How can I make Debian encrypt and decrypt my home folder when I log in/out like Ubuntu does?
The setup for encrypted home folder is described here for Ubuntu:
This should work on Debian as well, as Ubuntu is based on Debian.
However, you should consider whether full-disk encryption (i.e. encryption of / ) isn't more appropriate for you. Many programs will store personal data outside /home (e.g. /tmp, /var), plus swap will often also contain personal data leaked by swapping. So I'd advise to encrypt / and swap using LUKS. This is supported by the standard Debian installer; see the section in the Debian installation guide.