Sorry for the delay in response.
Yes, it is. Are you using a single field for the "summary", or multiple ones? How about if the customer wants to remove an item from the basket?
Yes this is possible. Read this article:
And this one, that comes with an example of an order form, but its more complicated than you probably want
And you'll find an example Rental Form here, that acts just like the order form you're asking aboutl