Paypal buttons can be added via HTML Snippets. You will be able to add a product selection and customize for different product options through Paypal's website. Paypal will automatically generate the code you need for pasting into HTML Egg's snippet.
Please note you will require an active Paypal account in order to generate code for shopping cart.
At the top of the page, select Tools > All Tools > PayPal buttons
Choose "Create new button"
Choose the button type you wish to use, select "Buy Now".
Customize button with your product information
If you wish for customers to have the option to adjust purchase quantity, please choose "Customize Advanced Features (optional)". For option "Do you want to let your customer change order quantities?", please choose "Yes".