Walmart has Scrubbing Bubbles Fresh Gel Toilet Bowl Cleaning Stamp, Rainshower, Dispenser with 6 Gel Stamps, 1.34 oz for $4.68. Shipping is usually free to Walmart+ members or on orders over $35.

About this product:

The Scrubbing Bubbles Fresh Gel Toilet Cleaning Stamp provides freshness with every flush. Simply stamp one of the toilet cleaning gel discs under the rim. Each stamp lasts up to 12 days! No touching. No scrubbing. No anything. Just continuous, flush-activated, freshening action. Scrubby calls it a hands-free way to help keep toilet rings and limescale build-up away. Stamp color may vary depending on fragrance. Odor-eliminating freshness every time you flush. That's cleaning reinvented.