Amazon released a Prime Exclusive version of the LG G6+ last year, with the usual pre-installed Amazon apps and widgets. It was already $300 lower than the cost of the regular G6+ ($499.99), but now the Prime model has dropped even lower to just $399.99 — about $80 off the usual price.
The G6+ has a Snapdragon 821 processor, a 5.7-inch 2880 x 1440 LCD screen, 4GB of memory, 128GB of internal storage (plus a microSD card slot), and a 3,300mAh battery. The phone originally shipped with Android 7.0 Nougat, but there are reports of an Oreo update from a few months ago (the product listing still says Nougat).
The Prime Exclusive G6+ is certified to work on AT&T, T-Mobile, and Verizon. You can get it from the link below.