Walmart offers the Repel Permethrin Clothing & Gear Insect Repellent Aerosol 6.5-oz. for $2.78. Opt for in-store pickup to dodge the $5.99 shipping charge. (Amazon charges the same with orders of $25 or more.) That's tied with last week's mention and the lowest price we could find by $3. It's odorless and purports to provide up to two weeks of protection.

Note: This is designed to be sprayed on clothing and gear only; it shouldn't be used on your skin.