intergrating payment gateways

Hi, I am hoping someone can help me I need to intergrate a payment gateway to our website and I am not a programmer, I am learning as I go along. I have installed S2Member to help me intergrate the gateway as our site is subscription based and S2member do tutorials for both the Paypal Standard and the Paypal Pro, albeit you have to pay for the Pro version with S2member.
The first question is, am I better to start with the PayPal Standard version and then Upgrade to the PayPal Pro version as obvious benefits are that the my members would not have to have a Paypal account then, which is obviously the best solution, but this would have to be done when more financial funds were in place, or it this a complicated way of going about this?
On the other hand should I go to the PayPal Pro version straight way, but then I would need to find help to try and install it, as I had tried going to the PayPal site directly and following their instruction to intergrate the Standard version, but I am afraid this has been too confusing for me.I have no idea how I would do the Pro version , as I am unable to find a tutorial for either via Paypal. Finances are tight and any help would be greatly appreciated. Dawn 🙂