Knotty, unfilled , unsanded, Some stain, high density new heart pine.
Not #2, no missing edges (wane), not punky loblolly or slash pine. True southern yellow pine.
4', 6', 8' long, will average 60% 6', 20% 4', 20% 8'. All 3/4" thick, 5" wide.
To cut cost this is unsanded, unfilled, machined long edges, ends untrimmed.
You install, fill, sand and finish, and this will be a great looking solid high quality floor. With your work you will have less than $2 a sqft in a great floor
Yes you may find #2 soft pine, at $1, BUT the waste will be 30-40% and you still will not have the hardness, and will have missing edges.