How can I get around using a debit card to download apps?

Payment methods that you can use in the iTunes Store, App Store, and iBooks Store - Apple Support

Read th above support guide (particularly section "Change or remove your payment method" and follow the steps/links there provided).

Regards

Giulio

Create or use your Apple ID without a payment method - Apple Support

You can't.

Many "free" apps include in-app purchase options.

Another alternative is to purchase an iTunes card and redeem

it to your account.

If you are asking if you have to have a debit card on file to downlod free app’s you simply skip where asked what payment you would like to use.