Xikezan via Amazon offers its Xikezan Waterproof Meat Thermometer for $10.99. Coupon code "ELA9878S" drops it to $15.19. Plus, Prime members bag free shipping. That's the lowest price we could find by about $1, although we saw it for $3 less in August. It has a temperature range of -50° to 572° Fahrenheit, auto shutoff, and requires two AAA batteries (not included).

Update: The price has since dropped to $15.99 before coupon, or $12.79 after.
Update 2: The price has since dropped to $10.99 without coupon.