That piece of software that allows you to download paid apps is called Zeusmos and believe it or not it has been developed by a 15 year old.
Zeusmos can be downloaded on the Cydia store for free which obviously requires you to have a jailbroken device but the thing that will scare developers the most is that Zeusmos can be downloaded even without a jailbreak making this service available to anyone with an iOS device.
Zeusmos can currently be downloaded for free on a jailbroken device and for a fee of $5/year it can be downloaded on a non-jailbroken device as well. It’s very strange considering you have to pay to pirate apps. Why not buy them in the first place?
Zeusmos can be downloaded by heading over to Zeusmos.com.