Sleeping Lamb via Amazon offers its Sleeping Lamb Large Capacity Diaper Bag in Grey for $36.99. Coupon code "9A6Y94HA" drops it to $27. With free shipping, that's the lowest price we could find by $15. It features a changing pad, stroller straps, and laptop pocket.

Update: The price now drops to $24.04 via coupon code "45SP6BXZ".