This Maybelline New York Instant Age Rewind Eraser Concealer ($8) is a bestseller on Amazon for brightening the under-eye area.
Customer Review: "I have horrendous dark circles. At any given time I am wearing at least four different concealers in an effort to hide them. On a really bad day, five. I'll admit, I was sceptical about this product, but, in desperation, I thought I'd give it a try and wow, am I glad I did. It has amazing coverage and is highly blendable into my other makeup, which is a real plus. It didn't fade over time like some of my other, more expensive, brands have."