Ply wood plank flooring ?

I think that what people actually do , is create a sort of platform floor. Sort of like a bed frame with slats, then the large pieces of plywood go over that frame. and you just have to figure out a way to avoid a small gap.

I do know that in my kitchen the beams hold up the floor and the "subfloor" ( plywood) has been laid pretty much on the diagonal. After that there is a layer of "paper" and then the armstrong vinyl flooring - which I think comes in 6' ? wide rolls. So you need to decide where to locate the seams . A tough decision, but fewer seams is generally better i guess.

In my basement which has a concrete floor the "ancient" asbestos tile is still surviving in a small area, and the much newer 12" vinyl tile ( also directly on the cement using whatever adhesive was recommended) is in pretty good shape, actually, after more than 20 years!

DIscussing a flooring for the concrete basement area, the vinyl tile has worked out. I believe we considered creating some sort of "subfloor" but decided that it was not worth the trouble and we really didn't want to have that big a difference ( or any noticable difference) in the height of the floor; since ceiling height was so limited.

With oak flooring the boards all have grooves on one side and a "ridge " on the other side. Therefore, they fit together and you don't have a problem with a seam that has a complete gap. At the doorways or transition points you cover up any gap with a doorsill or molding. I don't think - (although maybe?) there are any large pieces of plywood that are cut to fit together the same way an oak floor does.

You wouldn't be able to install the cut pieces of plywood on a cement/concrete floor unless you put down a sub floor which can get expensive--it would defeat the purpose of cutting the plywood into planks to save money on flooring! I would consider a floating floor that you can install over concrete in a basement. There are many flooring options available and you can do it yourself. Check with your local Menards, Home Depot, Lowes, etc. and any local flooring shops.

Need a subfloor and vapor barrier, but only if there is no moisture n floor . Since you have to do all the prep might as well put down a real floor g product.

Contrary to popular belief, plywood is not dirt cheap anymore.

Agree with Gk that the cost of all the tools and materials required to attempt this would be too expensive to realize any money saved.