Walmart offers the Frost King Reinforced 8x10-Foot Utility Cover with Grommets for $4.88. Choose in-store pickup to avoid the $5.99 shipping fee. That's $5 off and tied with last week's mention as the lowest price we could find. It's waterproof and weather-resistant.
These freebies are available to anyone with an internet connection, including both Amazon Prime members and nonmembers.