Yes, DaCast takes a small commission on each transfer done over the system. This commission is 9.9% plus $0.40 on each viewer purchase.
PayPal, bank transfer and other fees for processing payments are already covered in this, and there are no additional costs associated with selling content over Paywalls.
Note: The above refers to the process of selling content through the paywall. Fees might be associated with your payout request depending on your method and circumstance. Local banks may charge fees for receiving wire transfers. PayPal, for example, generally does not charge a fee for sending payment. Current exceptions, though, are sending money outside of the US, currency conversions and debit/credit card fees.
Please refer to the PayPal fees page here for explicit, up to date details on this: