Walmart offers the Summer Waves Solar Mat for $18.99. Opt for in-store pickup to dodge the $5.99 shipping charge. That's the lowest price we could find by $14. This mat measures 50" x 50" and purports to increase the temperature in a swimming pool by 5 to 10 degrees Fahrenheit.
The planet will thank you, your local (overwhelmed) landfill will thank you. Even your budget will thank you.