I tried this Maybelline Makeup Instant Age Rewind Concealer ($6) and immediately fell in love with it. This pick is a bestseller on Amazon, and for good reason.
The super-concentrated formula is infused with goji berry to brighten and illuminate the under-eye area while it covers up your dark circles. The soft, spongy applicator allows the formula to glide on smoothly; the product is evenly distributed across your skin. After a couple swipes, I simply tap the concealer with my finger until it's fully blended. You would never know I have rings under my eyes because they vanish instantly.