Each year, USPS adjusts their rates to account for changes in fuel and transportation costs. These changes oftentimes go into effect in January, which is the case for 2020. As of today, most USPS shipping services will have a rate change of around $0.40-4.40, depending on the service. In order to account for last year's postage increase as well as this year's, our threshold for free shipping in the US is now $65.00.
This year's rate change primarily applies to package services like USPS First Class Mail, USPS Priority Mail, and USPS Priority Mail Express. Stamps are still $0.55 like last year, so no need to make a post office run if you've got older ones kickin' around :)