Installing fonts into Debian for a single user is easy. Here it is in 3 steps
Step 1 - The .fonts File Folder
Looks into your home directory. We're looking for a hidden folder
~/.fonts
If you already have this folder then you can go to step 3, if not...
Step 2 - Making the .fonts File Folder
Open up your terminal go to your home folder and make the the .fonts file folder (this can also be done in the file manager of your choice)
mkdir ~/.fonts
you can check to see if it is there using
ls -a ~
See it there? Good! Time for ...
Step 3 - Copying your font files (.ttf) into the .fonts file folder
This can be done either on the command line or in your file manager of choice.
You're Done
That's it! If you open up an application that let's you choose your font, you should see your newly installed font. I can attest this works in OpenOffice and in GIMP.
As an example, try installing ecofont and save the world/your money by using less ink on your print outs.