Kaspersky for Android bundles on-demand malware scans and active web protection. Additionally, it implements a host of anti-theft features including remote locate, lock and wipe, as well as the ability to sound an alarm. You can even lock apps behind a PIN as an extra preventative measure in case your phone gets stolen. Although you need a paid Kaspersky Internet Security subscription to use all its features, some basic functionality is available for free. It's a top choice for Android antivirus apps.
Google Opinion Rewards is appropriately named. Google sends you surveys that ask you about places you've visited recently and you get Google Play Store credit for your participation. Polls don't come in very often, but you can increase your chances of receiving more, by enabling your location and answering surveys quickly and honestly when they do arrive. It's not going to earn you a ton of store credit, but it's enough to purchase an app or an album every so often. To add some perspective, one of our editors has earned about $64 since installing the app in late 2013. Droid App