So what are we looking at here?

FormBoss allows us to send multiple items to PayPal using something called the "upload method". This method is handy as we can send multiple items from one form, but slightly restrictive in that because it's not a real shopping cart:

a) it doesn't itemize items

b) doesn't allow us to change item quantities.

c) We cannot mix and match transactions types. Thus, if you have 1 shopping cart item on the page, no other types ones will work (such as a donation item).

And so, if you need a 'full blown' shopping cart, it would be advisable to simply use PayPal's built-in add-to-cart buttons in a custom form.

However, if these restrictions aren't an issue, read on!

The basic idea is that in order to process multiple items we need to do two things:

1) We need to set each item's 'Transaction Type' to 'Shopping Cart Item'.

2) We need to set the confirmation page's 'Process This Field...' property to Shopping Cart Items'.

So long as that's done, your e-commerce items should all be collected and sent to PayPal in one single group.