do i have to have a credit card on file in order to download free apps?

Yes, and No.

Create an iTunes Store, App Store, or iBooks Store account without a credit card or other payment method - Apple Suppor…

If you've already created your Apple ID, you'll need to add a payment method when you first use it to sign in to the iTunes Store, App Store, or iBooks Store. But you can optionally remove the payment methodafter you sign in to the store. You won't be asked for a payment method again until you make your first purchase.

If you haven't created your Apple ID, follow the steps in the article above, to create one and a store account at the same time, without adding a payment method