Costco launched a new "own your phone" program at Costco, where members get an everyday low price discount off of GS8 models (150 discount for GS8 and $170 discount on GS8+). Looks like an additional $50 is up for grabs during their 8/3-8/27 coupon period, making the discount $200 and $220, respectively. This price is even cheaper than the online unlocked deals and no trade in is required!
GS8: $549.99 final price plus tax. Requires postpaid activation/upgrade
GS8+: $629 final price plus tax. Requires postpaid activation/upgrade