I have a case where having a shipping cart makes the UX more cumbersome. The flow I want to achieve is:
1. The user is presented with a single list of 10 - 20 items.
2. All items start at 0 amount.
3. Users can hit a +/- beside each item to indicate how many he wants.
4. The user hits a "continue" button on the same view.
5. He/she sees a shortlist of the items he selected, amount, and total cost.
6. He/she hits purchase to finalize the order.
So what I want to get rid of is the back and forth dynamic of adding items to a cart. Since our store will online have a max of 20 items. And I want to make the experience as fast as possible:
Select how many He/she wants of each and hits purchase. That's it. Having to add things to a shipping cart makes sense for big collections of items. Not super small ones.
I understood your goal and I can help you to implement something like that, just contact me on firstname.lastname@example.org