Costco verizon smartphones - $225 costco cashcard back (makes Galaxy S7: $447, Galaxy S7 Edge: $567, applicable to iphone too)
Galaxy S7: $672 => $447 + tax on the original price
Galaxy S7 Edge: $792 => $567 + tax on the originial price
I did not check other phones though, but can be used for iphone 6s and others too.
The cashcard is a mail-in rebate, so the discounts are not immediate. You will have to sign up for the monthly installment plan (no contract), but you can pay it off if you want. For unlocking, you will have to stay for 6 months, though.
I was thinking of getting this deal for Galaxy S7 (or edge) (I am with Cricket now) and stay with Verizon for 6 months to get it unlocked. But a later research suggests that Verizon phones misses a few AT&T & T-Mobile LTE bands. This looks like a good deal for those who wants Verizon. It sucks that Samsung Pay is only available for carrier brands.
I am not sure if existing customers are eligible.