Play Store is a name for new shop with Android games and applications. Some of them are paid, but the price is really cheap. A lot of apps are for free of course. You can find Google Play Store in your Android phone in menu. It is the biggest portal with Android games and apps - you will love that.
Every game or application has ranking from other users. You can rate everything too of course. Apps and games are sorted in few categories and it is easy to find everything you want thanks to it. Play store is simply clever and full of interesting content.
If you are a developer, you can place your apps and games to Play Store for others. There is an easy way to earn some money. You can place ads into your apps or you can offer users some extra paid functions. Third way is to develop paid application and profit from it.