So Robert Downey, Jr. decided to pay for the kid’s bionic arm, right? Or is he just publicizing it? Either way it was bequeathed “at no cost to the family.” Downey says the bionic 3D printed arm is “affordable.” It’s from Albert Manero, the founder of Limbitless. A 3.13 Washington Post story by Leah Polakoff says the arm is 3-D printed on a Stratasys printer, [and] takes approximately 40 to 50 hours to manufacture. The average prosthetic limb costs around $40 K, but Manero’s “Iron Man” arm cost less than $350 in materials not counting labor, research and development time.