I am working to build a "store" (of sorts) where people can buy in to our project at various tiers. Since it's a book publishing project in addition to a community building effort, they'll receive a copy (or a number of copies) of the book in return. We're also wanting to work with a sort of "three-fold" shopping cart model we've just devised which takes into account the fact that financial support is not all people can offer to our project (relational capital, volunteerism, etc are equally important for us to grow).

Is there a good way to go about building a page or pages which will be able to have this sort of functionality? I am working on it, but finding the "donation" pages to be a bit limited for our purposes.