Can someone recommend a good ecommerce plug in

As always, it depends on your requirements. There are free and premium e-commerce plugins. I’ve used and recommend WP e-Commerce (http://getshopped.org/). It’s open source but for it to be really useful you need to purchase Gold Cart plugin which is $40 so it’s not too expensive.
There are of course other plugins WooCommerce (http://wordpress.org/extend/plugins/woocommerce/), Shopp and more.
Both support Paypal… The best thing you can do to is to download different plugins and test them out. It really depends on your requirements but I have been very successful with WP e-Commerce.

Also take a look at this topic: http://wordpress.org/support/topic/best-ecommerce-store-plugin?replies=34