Sunsmile*2013 via eBay offers this 6-Foot Waterproof USB Borescope Camera for $5.30 with free shipping. That's tied with our October mention as the lowest total price we've seen. (It's also a current low by $2, outside of the mention below.) It records at 640x480 at up to 30 fps.

A close price: Finetech007 via eBay has it for $5.33 with free shipping

Note: Allow up to eight weeks for delivery of either item.