If you are using your WordPress site for e-commerce, having a reliable shopping cart plugin is a must. Tips and Tricks HQ has designed the WordPress Simple PayPal Shopping Cart for this purpose. With a rating of 4.3 stars, close to 400,000 downloads, regular updates and great support, the plugin is definitely worth giving a try.
WP Simple PayPal Shopping Cart allows you to include an Add to Cart button on your posts or pages, as well as display the actual shopping cart in your posts, pages or sidebars. Visitors can see what they currently have in their carts, and remove products or change their quantity with a simple click of a button. Payments are processed via PayPal.