You can buy a variety of applications on the Google Apps Market. You can buy games for entertainment such as Angry Birds or you can even buy apps to help you with your everyday life such as a calorie counter.
Any Android phone or tablet that has access to the Google Play Market or Amazon's Android Market can buy books, movies, or music. You can also use the USB connection to move or copy material you already have to the public portion of the flash memory or SD card (if your device has one).
Most people download their applications on the Google play Store. However, it is possible to find your applications on 4shared or other shared servers. Note that it is illegal to download applications if you have not buy it before.
There are several free sales force automation cell phone applications available on the android market. You can also choose to buy a version with more user options. This is going to cost you anywhere from $1.99 to $5.99.
If you want it for an Ipad/ Iphone/ Ipod touch, you can go to the Itunes store and buy it or get he free trial. If you want it for Android, go to the Android Market. You can either do that from the tablet/phone or on the computer and sync it.