Amazon offers Prime members the Repel Lemon Eucalyptus Natural Insect Repellent 4-oz. Pump Spray for $4.97 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $6.62.) That's the lowest total price we could find by $3, although we saw it for a buck less in December. It's designed to repel mosquitoes for up to six hours and is DEET free.