J&R offers the Panasonic LUMIX G 20mm f/1.7 Micro Four Thirds Lens, model no. H-H020, for $319.99. Coupon code "CES2013" cuts it to $309.99. J&R Rewards members receive free shipping. (If you're not already a member, click here to join; it's free.) That's the lowest total price we could find by $37. It's compatible with Panasonic LUMIX G cameras.