Which security / privacy apps do you use on your Android phone?
I have found several free apps that I use. I won't take up space going into details about them since they all can be found in the Google Play Store at https://play.google.com/store. All of the following are free.
AdAway: This is an ad-blocker. Your phone needs to be rooted for this app.
LBE Privacy Guard: Your phone needs to be rooted for this app.
Lookout Mobile Security and Anti Virus: This app has both free and paid features. I only use the free.
Mr. Number: This call blocker works great.
OI Safe: This is a password protector.