Amazon has various Kuzy MacBook Silicone Keyboard Covers (which fit MacBooks with or w/out Retina Display) on sale for only $1 with $3.95 in shipping. That’s only $4.95 shipped! At the moment you can choose from blue, pink, purple or yellow.
Any prices listed in this post are current as of the post time. Prices at Amazon can flip fast, so don’t wait too long if you’re interested! When you’re done here, be sure to visit my Amazon section for all the best Amazon deals!