Blackberry app world is currently having a promtion called 'happy birthday blackberry app world' and has apps that have been reduced and even some free ones.
There are two types of Blackberry apps; paid and unpaid, while most apps will cost money, you can always find some good and useful applications for free!
"Most Blackberry apps have a fee to download or use. Some however are free. These can include games, messaging and social media apps as well as safety and weather alerts."
theres some warez sites out there like blackberrywarez.com ...
Similar to an iPhone, some apps are free and some you are required to pay for.
it is free to look at but there are some apps that you have to pay for but otherwise it's free to look at app world on blackberrys
Facebook, Quick search for google, blackberry messenger, whatsapp messenger, player for youtube.
Its a module that is required by some games and apps on blackberry.
RedTube
You have to go onto BlackBerry App World (which is where you can either buy or download for free different apps)and look for themes. Some themes cost money, but some are free. You'll have to find the right one for you :) Hope this helped :D
prankify yourself
"What is a popular app for a Blackberry depends on the class of the user. However, some of the more popular apps are PeeKa Who, TwitterBerry, YouMail and Viigo."
Blackberries have several popular apps pre-loaded, such as Facebook and Twitter, as well as some Blackberry-specific apps. Android phones also come with a variety of pre-loaded apps, though there have been recent security concerns about some of the software.