Handling payment with PayPal
You can use Excel's HYPERLINK to build a url, that can be used by your order form to open a shopping cart at Paypal.
The generated web page. Click on 'Click here to order' to see it in action
You can see additional things to set, for example currency, at
https://www.paypal.com/cgi-bin/webscr?cmd=p/pdn/howto_checkout-outside