Woot offers Emergency Mylar Thermal Blankets 20-Pack for $16.99 (orig. $29.99) + free shipping with Prime.

Product Description:
Primacare emergency foil mylar thermal blanket. The Mylar emergency blankets are designed to reflect heat back to body or deflect heat when used as a shelter from the sun, prevents post accident shock by retaining the patient's body heat. Measures 82-inches length by 54-inches width.

• Compact emergency protection
• Lightweight packaging
• Durable insulation Mylar material
• Measures 82-inches length by 54-inches width