Yep, Virtua Tennis for Android is actually pretty good. The graphics look great and the gameplay is terrific. However, it also has flaws. You cannot personalize your characters with different items and you don't get to play with the tennis greats like Federer or Nadal. Your opponents are all made up names and not actual tennis players. Still it's a lot of fun and is really hard to put down once you've started playing it.
I bought a Minecraft app for my son to play with so he would not talk incessantly whenever we are at the doctor's or dentist's office. I also paid for a Yoga app that had a free option but could be upgraded to a full version. It was cheaper than buying a yoga DVD so I saved money with that purchase. For the most part though, I install free apps.
I have never paid for an apparently and never intend to. Simply because there is nothing that I need desperately enough to buy it. I'm content with free games and don't need any paid services for my smartphone. Until the day comes when I need something for work, I won't be spending dosh on apps.
I still buy apps. In my whole lifetime that I have had my iPhone I would have to say that I bought about 10 dollars worth of apps and I honestly don't think I will be needing any other ones. It just seems like everything else can be bought for nothing so I find paying extra money for something that can be found free is a rip off.
