kexcelled TPU 64D Filament Black, High Speed Elastic and Flexible 3D Printing Filament Rigid Hard TPU for AMS,Durable and wear-Resistant,1 kg Spool (2.2lbs)

Amazon-only with a wide SKU list: PLA through TPU, including silk and specialty variants. Prices sit at the low end; quality is consistent enough for general use.