The Postal Service has already shared with mailers information on its plan to change to Zone pricing for origin entry Marketing Mail and Periodicals through its classification filing at the PRC.  

More details continue to be released, but are subject to change before the official January filing. Mail will continue to be presorted, paying presort rates based on the container (bundle/tray) level, but now origin entered mail will be paying a zone price for entry based on the distance from origin to destination.  For mixed bundles and trays there will be a flat rate, not variable by distance.  Below is a rendering of a planned 3602 for Marketing Mail.

The USPS 3D base Service Standard Directory for Marketing Mail, Periodicals, Pkg Service and First-Class Mail uses a 3D to 3D ZIP Code directory listing the expected service days based on combination of origin/destination ZIPs.  

That same listing can be used now to identify what the Zone will be based on where entered.  Using the First-Class Mail (FCM) column you can assign the Zone based on the service days.  Using ZIP Code 601, this example shows some sample zones based on the destination of the mail.

2=zone A
3=zone B
4=zone C
5=zone D

You can also use the USPS Service Standards Map to see a visualization of the planned zones based on origin ZIP. Below is using ZIP Code 60119.  Click on the map to enter your own mail class and ZIP Code.