Welcome to Shopify Community. My name is Olivia and I work here.
I'd be glad to help answer your questions today. It's correct that our Basic Plan is $29 USD/month + any applicable taxes if Shopify has a business presence in your jurisdiction.
Here are the four sections you can find on your invoice:
Subscription shows the charge for your store's Shopify subscription plan. If you switch your store to a lower subscription plan within a billing cycle, then a subscription credit is applied in this section.
Apps shows app charges associated with the bill. App charges are set by the app developer. App developers can charge for apps with recurring fees, usage fees, and one-time fees. If you have an issue with an app charge, then contact the developer for help.
Shipping shows charges for your shipping labels and adjustments made during your billing cycle.
Transaction fees shows transaction charges associated with the bill. You are charged transaction fees if you are not using Shopify Payments.
You mentioned you have removed paid apps, so let's rule out any of these other possibilities by taking a closer look at your bill. Please head to Admin > Settings > Billing to pull up your latest invoice and open it for further details. There you will see an overview of all charges in USD, which is then converted to your local currency (if applicable).
Please feel free to share a screenshot of your invoice with me here if you need an extra hand navigating it. Please make sure to crop out any personal or identifiable information before you share it back with us on this public space.
I look forward to connecting.