Two awesome deals for you! While Lumia 1520 is back to $199 on-contract pricing at AT&T post Black Friday, Amazon is giving $100 discount and is selling on-contract Lumia 1520 for $99 only. This looks like best on-contract pricing for Lumia 1520 at the moment.
Verizon is offering savings of $200 on Lumia 2520. While $100 is due to its promotion on 4G Tablets, another $100 comes in picture, when you buy it in combination with a Lumia 928, which is now free on-contract at Verizon. This makes it best Lumia Phone + Tablet combo deal in US. In comparison AT&T gives $200 off on Phone + Tablet bundle but none of the eligible devices Lumia 925, 1020 and 1520 are free on-contract.
You may be interested in reading our Lumia 928 review, before making a decision.