Amazon offers Prime members the Fred & Friends Ninjabread Men Cookie Cutters 3-Pack, model no. NBREAD, for $7.93 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $6.14.) That's the lowest total price we could find by $2, outside of the mention below. Each cutter features a different pose, and they're made of ABS plastic.
A close price: Costume Hub via eBay has them for $9.16 with free shipping.