What to do after jailbreaking..
After Jailbreaking your iDevice you will find cydia on it(picture below of cydia) through cydia you can add sources, or websites where you can install apps from 1. Look for the cydia icon on your iDevice, go into cydia, go to manage, then hit sources tap edit(top right) then add (top left) ,Type this url in there "http://cydia.hackulo.us" and hit finish.
After it's added go to manage, sources, and select hackulous, once you've selected the source, it will show you a list of all the apps hosted by that source. Find Installous, and install it..this will be where you get your apps from. it's exactly like the app store, except any app through installous, is free..