What ScottC is suggesting is that you create a business account with PayPal:
https://www.paypal.com/us/cgi-bin/we...merchant&nav=2 and your users will not have to sign-up to pay with a credit card.
PayPal charges a small fee to complete the transaction but credit card companies charge something similar for merchants.
You can also use something like Google Checkout though I am not sure your country is supported.
I am not sure what you mean by "relying solely on PayPal".