The paypal snippet is very easy to set up and use. In it’s simplest form, you just modify the snippet with your info (like your paypal connected email address), then manually call the snippet with the relevant parameters:
[!PayPal? &price=`100` &name=`the product`!]
It will create essentially the same button that you could create using the Paypal tool
https://www.paypal.com/us/cgi-bin/?&cmd=_button-designer&factory_type=cart