Walmart has a couple Tone Fitness Vinyl-Coated Kettlebells on sale listed below from $3.50. Select free in-store pickup, otherwise free shipping if you spend $50 or more.

• 5lb. $3.50
• 10lb. $6.50

Optionally, you may buy both the 5lb. and 10lb. together for $9.51 if you scroll down on the 10lb. product page to where it says "Buy Together & Save" and click "Add all to cart".