Math for s20:
$999 normal price
-$200 for this sale so $799 shipped with no discounts.
-$40 If you use a referral code (despite such codes claiming they are good for 5% off and samsung's site claiming that too, you only get $40 off).
-$80 If you use student or government discount you can get this additional discount
Up to -$370 for trade in a galaxy Note 10 (though they VASTLY reduced trade in on the galaxy S7 which used to be $300 but now is only $25-$55). Potentially getting a samsung galaxy S20 upgrade for as low as $310. If you do trade in, MAKE SURE to click the $200 sale first. You will get the option for trading after you click that.
Similar math for the other S20 phones, the student/gov discount goes up a bit though ($100 for the S20+ and $120 for the S20 Ultra). YMMV on the trade in trying to combine it with the $200 sale.
They give you 4 months of youtube and 6 months of spotify for free if that is a factor
You can enroll in the 2 year buyback and they will pay you 50% of the phone price in two years
They offer 0% financing for 2 or 3 years (can get under $20 a month) if that's desired.
Although there's a link on their page claiming a $50 accessory credit in a one day sale, I've not found out how to use that.