Webform Paypal

Download Paypal Webform Module
Download Webform Module
and enable

Go into config of Webform (from the modules screen) and select the Content Type that you want the Paypal button to appear under

Create content for that content type, save and go back into Webform tab
Create a field, using Paypal button

To get the Button ID, log into Paypal

Note: it cannot be a personal account - must be premier or business (if personal, go into account and select 'upgrade' )
go to Merchant Services
Sell Online
My Selling Tools
Manage my Payment Buttons
Create a new button and the Hosted Button ID will be in the code (the name of the button will be the product description shown to the user when they go through to Paypal)
Here is quite a good tutorial I found about the actual button creation process:
http://learnwebtutorials.com/set-up-paypal-buy-now-button