Triboelectric nanogenerators (TENGs) are emerging as a new panacea for sustainable energy generation through the conversion of random mechanical motion into useful electrical energy. The present TENGs are fabricated via bottom-up approaches using novel nanomaterials (e.g., graphene and carbon nanotubes) and patterned polymers (e.g., polydimethylsiloxane or PDMS), which limit the deployment of TENGs at scales ranging from microelectronics to grid integration. Here we demonstrate a top-down approach for fabricating low-cost and ultra-simple TENGs (U-TENGs) using off-the-shelf materials for immediate proliferation into the present energy landscape. Specifically, U-TENGs constructed using indium-tin oxide (ITO) transparent conducting nanofilms on polyethylene terephthalate (PET) and polyimide/Kapton adhesive tapes is demonstrated. U-TENGs are robust (>20,000 cycles) and inexpensive (~$0.06cm−2) with <5min fabrication time, can achieve a peak voltage of ~500V and power densities as high as ~490μWcm−2 without the need for any nanopatterning, and operate over a wide range of temperatures up to 60°C. Several practical applications of U-TENGs such as LED lighting, powering electronic calculator, textile integration, and passive vehicle/pedestrian monitoring are demonstrated.