OK, as requested, I reproduced the issue on www7.
If you click "Hide Price" on a product, the price is not shown on the product list page. Expected behavior.
Add to the cart, and no prices show up in the cart, BUT the total shows up (See screen shot).
The expected behavior is that the price would be in the cart, just not on the product listing page.
This is slightly different in 4.0, where the price field is populated with "Request a Quote". Now it just doesn't show anything.