With orders of $25 or more, Amazon offers the Taylor Precision Instant Read Digital Thermometer for $5.06 with free shipping. That's the lowest price we could find by $3, excluding the mention below. It measures temperatures from -58° to 302° Fahrenheit. Note: This is part of the Amazon "add-on" program and can be purchased only with orders of $25 or more.

A close price: Zoro via Walmart has it for $5.75 with free shipping.