By Kirk Miller It’s Earth Month, and several brands with an eco-friendly pedigree and mission got together to help. Not just the planet; they’re also here to help you with discounts up to 40% off. The 13 brands behind the Better With Friends sale are all Certified Climate Neutral — basically, each brand measures the amount of carbon they’ve created every 12 months, then “zero it out” by reinvesting in renewable energy (you can learn more at this video here). The Better With Friends flash sale, today only, promises up to 40% off at a variety of online stores. A few standouts: BioLite: 20% off s…