Why am I being charged to download free apps?

This isn’t helpful. It doesn’t answer the question directly

You can download free apps, but you may need to have a valid payment method on file, even if the app you want to download is free. 

Free apps has also In-app pruchase.

See -> Buy additional app features with in-app purchases and subscriptions

Buy additional app features with in-app purchases and subscriptions

See also -> Apple Media Services Terms and Conditions

Legal - Apple Media Services - Apple

If you have received an invoice from Apple, on every invoice from the Apple Store and/or iTunes Store always states what you have purchased (and/or concerns a subscription) and the amount.

Tap on Report a problem on the invoice.

Or try to ->  Request a refund for apps or content that you bought from Apple.

Request a refund for apps or content you've bought from Apple – Apple Support (UK)

If you have requested a refund, you must wait until Apple has approved. Then you will receive a message from Apple.

Refunds are not guaranteed. For more information, see the Terms & Conditions.

why am i being charged $30 to download a free app

check you haven't subscribed to the same service twice, once through Apple and a second time directly with the service provider. E.g., Join Apple Music on your iPhone, iPad, iPod touch, Mac, or PC - Join Apple Music - Apple Support - "Make sure to join Apple Music through either Apple or your mobile phone service provider, so that you're not charged by both."

Click on this link to read what to do "If you see ‘itunes.com/bill‘ or an unfamiliar charge on your bank, credit card, or debit statement" --> If you don't recognize a charge - Apple Support Note, if you are a Family Sharing organizer, purchases or subscriptions made by another family member may be charged to your card but will not appear under your purchase history or subscriptions. Ask family members about those or check the email receipts Apple sends you for any purchase charged to your Apple Account.

If you need further assistance contact Apple; start here --> Billing & Subscriptions --> https://getsupport.apple.com/?PGF=PGF63006

Exactly it’s just stating the obvious

You probably owe money for something you bought in the past.

Apple is charging me 1.99 every time I download free apps even apps I downloaded already it’s charging me 2 dollars every time why?

That’s weird. 🤨 maybe you forgot about Family Sharing?