Paypal does not have a monthly fee so I'm not sure what your talking about. I belive you've been misinformed.
PayPal is going to take a Percentage of of the sale... However so is any other Processor, however with paypal unlike other processors there is no setup fee and other ongoing fees you only get fees from paypal when you accept money.
So I'm afraid you want to accept payments via credit cards and want it for free I'm afraid your in for a suprise when your not going to find this is an option anywhere. These companies are accepting the risk of the payment and their other services are worth getting paid for...
People who want to be in business and not want to pay to play don't stay in business.
Usually with a third party system or Internet Payment Services Provider (IPSP), there are no monthly fees. And usually with a merchant account, there is no set-up fee, but usually a $10-$20 a month fee.
The gateway might have a set up fee, anywhere from $25- $300. Some gateways won't charge you a transaction fee (on top of the transaction fee that the merchant account provider will charge). Some gateways might be a bit more expensive monthly but give you so many transactions a month for free. This sometimes is cheaper if you have a lot of transactions.