BuySpry via eBay offers the refurbished second-generation in Space Gray or Gold for $629.99 with free shipping. That's tied with our refurb mention from a month ago as the lowest price we've seen for this model in any condition. (It's also $219 less than you'd pay for a new one today.) Features include:

2732x2048 LED-backlit Retina touchscreen display with 120Hz refresh rate

A10X 64-bit chip

4GB RAM & 256GB internal storage

12-megapixel rear camera & 7-megapixel front camera

up to 4K video recording

802.11ac wireless & Bluetooth 4.2

fingerprint sensor

iOS 10

Note: A 60-day BuySpry warranty applies. The item may show minor signs of wear.