Not sure what app you are using, but any app that charges you $29.99 to withdraw $5000 and claim that they are saving you 70% sounds suspicious. I also do not see how Apple is involved in this transaction at all. It appears to be between this App and PayPal. Apple does not get a service fee just because you are using an iPhone to make a transfer.
As you can see from the previous provided link on transactions fees using the Apple payment method, there is only a fee on Instant Transfers. The fee is 1.5% up to a maximum of $15, so the $100 number shown in the app does not make sense. In addition, you can avoid the fee altogether using the Apple service altogether by using the normal transfer method of waiting the 1-3 days.
Hopefully this is a legitimate app that you have given them your PayPal account number to.