Walmart the Mrs. Meyer's 33-oz. Clean Day Liquid Hand Soap Refill in Basil for $5.64. (Amazon charges the same with orders of $25 or more.) Opt for in-store pickup to avoid the $5.99 shipping charge. That's around a buck less than what you'd pay at other local stores.

Update: Amazon now offers it for $5.36 $5.98 via Subscribe & Save. Be sure to cancel Subscribe & Save once your order ships to avoid being billed for subsequent shipments.