The first fork is not price, wood or decoration. It is Arabic or Turkish, and both are correctly called an oud. Turkish instruments are built to a shorter scale and are usually tuned higher, which gives a tighter, brighter, more immediate sound. Arabic instruments are larger with a longer string length, and the extra length is what produces the deeper, rounder tone most people picture when they hear the word.
Neither is the beginner's instrument or the serious one. What matters is which repertoire you are learning and, quite practically, which one your hands prefer: a shorter scale is easier to reach across, and on a bare fingerboard reach is not a detail.
What a bare fingerboard changes about buying
There is nothing on the fingerboard to check for wear, no sharp ends to catch a hand, and nothing to blame when a note is out of tune. What replaces all of it is the neck's straightness and the fingerboard's flatness, because a dip or a rise in the board is heard directly as intonation rather than as buzz. Sight along the fingerboard in good light before anything else.
A floating bridge and no truss rod
The strings pull on a bridge held in place by their own tension rather than by glue or bolts, and there is no rod in the neck to adjust. That means the instrument you are looking at is essentially the instrument you will own: action, relief and geometry are the builder's decisions, and changing them is real lutherie rather than an afternoon with a hex key. Judge accordingly.
Pegs
Most ouds use friction pegs — tapered wood, held by fit. Good ones are a joy and bad ones will make you hate the instrument, because eleven or more strings that will not stay where you put them is not a small annoyance. Turn every peg. They should move smoothly and stop where you leave them. Pegs can be refitted, but if a seller says "they just need a bit of chalk" on all of them, that is a repair being priced as a quirk.
How to test one
Play open courses first and listen for whether both strings of each speak together. Then play a simple line — a shape from the chord library, or the first tones of jins hijaz — slowly, up the neck. You are listening for whether the instrument stays in tune with itself as you move away from the open position, which is the one thing an instrument with no marked positions cannot fake.