Never-MSRP via eBay offers the Unlocked Samsung Galaxy S7 Duos Dual-SIM 32GB 4G LTE Android GSM Smartphone, in Gold, model no. SM-G930FD, for $645.99 with free shipping. (Tropical Mobile via eBay offers it in Black for a buck more.) That's the lowest total price we could find for an unlocked dual-SIM model by $32. It features an Exynos octa-core processor (2.3GHz quad-core and 1.6GHz quad-core), 5.1" 2560x1440 touchscreen AMOLED LCD, 4GB RAM, 32GB internal storage, 12-megapixel rear-facing camera, 5-megapixel front-facing camera, 4K UHD 2160p video recording, 802.11ac wireless, Bluetooth, microSD card slot, water-resistance, and Android 6.0 (Marshmallow).

Update: It's dropped slightly to $644.99.