Take a look at a Moodle plugin called Elightenment. It's a new paypal plugin for Moodle 2.7 and 2.8 that was first released in February 2015. It also offers support for shopping cart and discount code. Haven't tried it yet myself but it is on my list of plugins to evaluate over the next few days.
If you do give it a spin, I'd appreciate hearing your thoughts on it.