If you're getting short on pens and pencils don't go out to the store to buy new ones. Just do what I do -- put your hand in between the cushions of your sofa and you'll be sure to find anywhere from 5 to 10 pens and pencils. You'll save a ton of money doing this.
I don't think I've bought a pen since at least 1996, my freshman year at Loyola, when I started finding and keeping left-behind pens at Cudahy Library, which were there in spades (as they surely are in most any other library).
Then, when I started teaching, I was forever finding pens on the floor at the end of the day, which I gladly made my own.
Now, I find, free pens seem to be everywhere.