We have a very small bathroom, which means there's limited storage space. When I redid this room I had to come up with a place to put a few extra rolls of toilet paper. I didn't want it sitting out in the open, so I figured out a way to hang a few rolls in the vanity.
Inside the cabinet, there is a bit of extra space between the sink and the bottom shelf, just enough space for 3 rolls of toilet paper, so I came up with the idea to put a board across the side so that I could attach 3 door stoppers to it (you know the things you use to keep a door from hitting the wall?).
The stoppers are long enough that they hold a roll of toilet paper and they are out of the way, so you can just reach in and grab one. An effective, easy and cheap (less than $6 for the stoppers) storage solution.
To see more: http://www.chatfieldcourt.com/bathroom-redo-details/