Tenergy via Amazon offers its Tenergy Odev Geo STEM 2-in-1 Salt Water/Solar-Powered Robot Car Kit for $19.99. Coupon code "RAOMWYVN" cuts it to $14.99. With free shipping for Prime members, that's the lowest price we could find by $8. It requires no screws or tools and can be assembled within 15 minutes. Deal ends April 18.