Quick calc gives me a total of about 2.2 cubic feet. I'm sure you'll need extra for waste tho. Might want to wait for input from others as I'm neither a pro installer nor mathematician. That being said, I understand that polymeric sand is a better choice for this application. The added binders lock everything together, preventing washout and seed germination.
the size of the "pavers" and the joint spacing/gaps take them out of the normal definition of pavers with real strength.
You are only dealing with a few cubic feet get enough of the over-priced sand since the cost in time, effort and fuel to get more will be more than wasting some material. Really, the sand and "pavers" should be vibrated to work the sand into the joints. I have never seen a major paver installation that used polymeric sand, especially when it is a serious 20-40 acre heavy load site, but a patio will not be a critical use.