Amazon offers the Mothers California Gold Clay Bar System
, model no. 07240, for $12.93. Add it to cart via Subscribe & Save to cut the price to $10.99
with free shipping
. That's tied with last month's mention and about $2 under what you'd pay in-store locally. It includes two clay bars, Showtime instant detailer, a microfiber towel, and purports to remove embedded grains of metal, tree sap, airborne environmental deposits, and paint overspray.
Be sure to cancel your subscription once your order arrives to avoid being billed for subsequent shipments.