NO, you should never ever pay for a Jailbreak.
People who develop jailbreak do it for free. Some people might ask charge you to Jailbreak your device for you and if it makes you feel better to pay someone, you can do that but why pay when you can jailbreak your device yourself for free.
Is Jailbreaking Legal?
Yes. Jailbreak is completely legal. It was considered illegal for a long time but in July of 2010, a rule was passed by the Government that made Jailbreaking legal.
Does Jailbreaking an iOS device voids its warranty?
The answer to this question is yes and no. If you Jailbreak your device and go to an Apple store or service centre, you won’t receive any kind of customer support because you voided your device’s warranty the minute you jailbroke.
However, if you really want to take your device to the service centre, you can always restore it to its factory settings from iTunes which will bring your device back to the way it was when you first bought it and Apple will have no way of telling whether your device was ever jailbroken.
Is Jailbreaking and Unlocking the same thing?
NO. Jailbreaking your device is not the same as unlocking it. They both are two different things. Jailbreaking allows you to install third party applications, tweaks and mods on your iOS device while unlocking allows you to use your iPhone on a different carrier.
Can I get paid apps and games for free after Jailbreaking my device?
YES, you can. Installing some tweaks can help you in getting most of the paid applications and games for free.