password used every time

You may find these links useful:

<<Family Sharing - Apple Support>>

and then in the

"Making purchases is easy. So is setting limits."

section:

<<Request and make purchases with Ask to Buy - Apple Support>>

The Family link has to do with the first link that you were provided. That contains instructions on how to set up Family Sharing. If you just setup the device with your Apple ID, and did not create a Family Sharing situation, then go to Settings>iTunes & App Store>Password Settings>and select Always Require.

Then you don't have an iPhone 4s, you have an iPhone 4. I don't necessarily remember the exact controls in iOS 7.1.2, but you are saying that if you follow the path that I provided you, then you do not see the ability to make those password changes in the iTunes & App Store area? Then I could not tell you exactly. The passcode ability has to be set somewhere dealing with the App Store. What happens if you go to the App Store area under Settings, or the iTunes store area?

Glad you were able to get it. Without a device with the older iOS, I couldn't do any better than I did.