Airbay via Amazon offers its Airbay Liquid Chalk Markers 10-Pack for $11.92. Coupon code "M7FS5LYG" cuts it to $8.34. Plus, Prime members bag free shipping. That's a buck under our July mention and the lowest price we could find by about $5. They feature reversible bullet/chisel tips, are 100% water based, and easy to clean.