Don't waste your time or nerves on this plugin. The directions seem simple enough, until you actually try to sell something on paypal. When your customer gets on paypal, they get this message: Things don't appear to be working at the moment. Please try again later. Result: Lost sale. Don't try getting through to support. It does not exist.
In this case all of the critical custom data stays on PayPal (or 2Checkout) and is never posted in your WordPress dashboard, something that does occur even if you use PayPal with one of the shopping carts mentioned. However, you do lose some of the purchase options explained earlier which is a major advantage to a WordPress shopping cart in the first place.

But this isn’t a post extolling the virtues of WooCommerce. Instead, let’s look at how we can customize parts of it. Specifically, I want to look at the cart. WooCommerce is super extensible in the sense that it provides a ton of filters and actions that can be hooked into, plus a way to override the templates in a WordPress theme. The problem is, those take at least some intermediate-level dev chops which may not be feasible for some folks. And, at least in my experience, the cart page tends to be the most difficult to grok and customize.
What makes the WordPress PayPal plugin a truly reliable choice is its PayPal Sandbox support. This is a simulation environment with which you can perform some test purchases between a test buyer and a seller account. By using this option, you will ensure that you don’t run into any issues once you decide to use the plugin and sell your products to the customers. You will also be able to allow users to add multiple items to the shopping cart and checkout, view or manage orders received via PayPal buttons directly from your WordPress admin dashboard, and more.