The Ordinary Vitamin C Suspension 23% + HA Spheres 2% ($6) Guess what? This $6 anti-aging serum is the biggest new thing in skincare. Why? Because my favorite vitamin C serum costs almost $200. Dermatologist Ross Perry, MD, confirms the active ingredients in each affordable bottle (like vitamin C, hylauronic acid, and retinoid) are "well proven, tried and tested ... and are very cheap to source."