When I was in school, I was poor. (duh) And this is how I and all my poor compadres effectively and cheaply carried our brushes to and from class every day. This method is so efficient that I used it for years. And years.
The prior artist brush carrier tutorial (parts one and two) was certainly prettier but as this holder is both cheaper and easier, it falls into the "Simple Solutions" category.
NOTE: If you work horizontally, cut your elastic longer - about 30-35" each.