Hey, @RealSteelGuys. You’re right! If you are based in the USA and using Shopify Shipping, you should be able to set up calculated shipping rates with USPS. The additional feature that’s included in the Advanced plan, Carrier Calculated Shipping, is for merchants who have their own business rates established with USPS, FedEx, UPS or Canada Post, and would like to offer those rates to their customers.
That being said, let's look more closely into what’s happening on your account. In reference to “getting the shipping information to come up”, are you referring to your USPS shipping rates not appearing on the shipping page within your checkout when making a purchase?
If so, please start by confirming the following:
Let me know once you’ve confirmed the above parameters. Or, if you had to make any adjustments and are still not seeing USPS rates in your checkout, we’ll continue to troubleshoot this together to get it working for you.