Limited access to prosthetic devices affects 35 million people in developing nations, where traditional prosthetics cost $3,000-15,000 per device. This engineering study explores 3D printing technology for creating affordable, customizable prosthetic solutions. We designed and tested 15 upper-limb prosthetic prototypes using PLA and PETG materials, conducting durability testing over 10,000 cycles and user trials with 23 participants. Results demonstrate functionality comparable to conventional prosthetics at 8% of the cost ($240 average). User satisfaction scores averaged 8.2/10, with 91% reporting improved quality of life. The research includes open-source design files and manufacturing protocols for global implementation.