Good question. For Mass Pay API, you actually need a business account. I don't think there is any extra fee though other than the usual transaction fee that paypal charges.
The links I posted suggest the sender pays a fee upon use of MassPay, otherwise, no. There is no extra fee. Though I don't have a business account, so I don't really know what that entails.
The links I posted suggest the sender pays a fee upon use of MassPay, otherwise, no. There is no extra fee. Though I don't have a business account, so I don't really know what that entails.