How to pay for OSP?

Excuse me, I was just wondering about the process of paying for OSP. Could you please explain the steps I need to follow in order to make a payment? Do I need to have a specific cryptocurrency wallet or can I use a credit card? Also, is there a fee associated with making a payment, and if so, how much is it? Lastly, how long does it typically take for the payment to be processed and confirmed? Thank you for your time.