Quidsi Retail LLC via Amazon offers the Crest 3D 5-Minute Touch-Ups 56-Count Kit
. Plus, Prime members receive free shipping
. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping starts at around $5.) That's the lowest total price we could find for this quantity by $29. It purports to remove stains and is enamel-safe.