The easiest and cheapest way to keep your cutting board from slipping is to put a damp paper towel or damp kitchen cloth under your cutting board. This creates friction between your board and the counter to keep things from slipping.
If you want something more reusable (or get tired of wet towels!), try a non-slip mat like what we have in the picture above. You can make one yourself from the same material used to line your drawers or keep your rugs from slipping. Rolls of this non-slip material are available at places like Home Depot and Target for around $5.
One more step up is finding a cutting board that has non-stick "feet" on the bottom surface. We've seen these ranging in price from $5.99 to $36.99. You could also make one for yourself by putting a ball of tacky-putty (the same putty you used to hang posters in your college dorm room!) underneath the corners of your cutting board.
Here are a few sources from Amazon:
(Image: Emma Christensen for the Kitchn)