Walmart has Scrubbing Bubbles Continuous Clean Drop-Ins - One Toilet Bowl Cleaner Tablet Lasts Up to 4 Weeks, 5 Blue Discs, 7.05 oz for $5.77. Shipping is usually free to Walmart+ members or on orders over $35.

About this product:

Scrubbing Bubbles Drop-Ins are just the remedy for yucky toilet stains. Just drop a tablet into your tank to help keep your toilet bowl stain-free up to 4 weeks. With every flush, your toilet enjoys glorious relief from stains caused by hard water, minerals and limescale. That's continuous odor protection for a continuous Cleaner. Quick and hassle free! Stain and smell protection that drops right in. That's cleaning reinvented.