Here are some sorting activities you can do with free materials. Find more sorting activities on the math sorting page.
This tray came from Big Lots and was originally a planter, but it makes a great sorting tray.
Sorting Paint Cards
These paint sample cards are the kind you can pick up for free at the hardware store. I get different hues of each color for the children to sort.
I always have tons of buttons that I collect from the extras on new clothing. Ask families to collect them also. These are sorted by the type of hole they have: 2 holes, 4 holes, & a loop hole on the back. They can also be sorted by shape or color.