free, detailed instructions at usps.gov
basically by zip, then by the -1234 number.
for less and a few hundred ( I forget the exact number) it’s not worth it and you should mail first class with a stamp. It costs more but has a better delivery rate.
If you have a high quantity of mailers…
I will CASS certify and sequence your list for free so you can get the lowest postage rate (lower than if you just sort by zipcode)
However…when you apply your sticky labels, you will need to keep the pieces in order ( I will include a sequence number in the address block) and you will need to borrow someones bulk permit number there locally.
I will also email you the required paperwork (already completed) that you hand in with the pieces.
email me: