I don't know your total woodworking skill and toolset, so I might be taking a bit of a leap with this Answer.
The wall paneling you link to is EverTrue tongue-and-groove paneling. This has a generic profile, a sample of which I've pasted below (source: Vermont Lumber)
This is actually quite simple to make yourself out of regular pine boards, if you have the right tools and skillset (not to mention the patience to do this for a couple hundred linear feet of board). I will list two options below for your consideration.
Table Saw Method
Using a table saw, one would stand the board on edge to trim out the groove (on the left side of the image above). Then, one would lay the plank flat and run it though the blade (in a couple of passes) to create the tongue on the right side. Then, tilting the blade of the table saw, one trims off the chamfers on both sides of the board to match the profile (or not, depending on your personal preference).
Hand Plane Method
The next method assumes that you have, or have access to, a set of wooden match planes (also known as tongue-and-groove planes)
or a plane similar to a Stanley #48 or #49.
You could even make use of a plow plane for this task, though it would be a bit trickier than the above two planes. You would use these to make the tongue and groove in the board, then create the chamfer using a block plane or a rabbet plane.
For finishing, @Graphus's answer above covers everything that I could possibly discuss, so I'll direct you there.