Get it from Amazon for $6.99. Also available in three other primer colors.
Promising review: "A must-have for shadow enthusiasts. I apply once in the morning, and it lasts the duration of long days (16+hrs). It makes your shadow really pop, especially lighter/brighter colors. Although it does not make it 'smudge-proof,' it certainly helps avoid smudges when you accidentally rub your eyes. I have sensitive skin, and this product does not irritate my skin. It works with all brands of shadows. Applied every day, one capsule usually lasts 6-9 months. I will be a long time user of this product!" —Trish