if an app is free in the Apple store why is apple trying to run my credit card ? ill be **** if they are ever getting my acct number for anything again

You don’t need to have payment information in order to download a free app or on your account at all for that matter. If you have a pending charge in your purchase history/an unpaid balance, you will be prompted for your payment information when trying to download an app.

Check and see if you having a pending charge by going to settings> your name> ITunes and App Store> Your Apple ID> Purchase History

There not running or billing you, its for verification purpose.