Not to be harsh, he really is a cute little colt, but I personally
wouldn't pay more than $100 for him, if that, and only if he's well papered. Only because of the retained testes, to be honest with you. I'm rather fond of smaller horses, and your guy not only looks smaller, but looks freakishly adorable to boot. The retained testes though....erf. I don't mind scarred horses, I had a badly scarred one myself, but a half-stallion is cause for alarm
I don't know how much you have sunk into him, but thirty days at a good trainer (not top-of-the-line, but not a bronc breaker) will really increase his value and allow for a better evaluation of his temperament. There is absolutely nothing wrong with having a five year old unbroke horse
. ESPECIALLY more delicately built Arabians, in fact I prefer it far more than a horse broke at 2 or 3. Those joints are not meant for the kind of stress you need to put on a green horse. Light training and socializing is all they need until they are mature. THEN send them off to be broke!
I have a coming two year old who won't see a person on his back until he's at least 4-5, depending on how he matures. I have a five year old I bought as a two year old who's going to the trainer in a month or so. He's matured enough to handle the work load, now that he's stopped growing. I even have a coming six year old (I bought him as a just-turned-five) who's going to be broke out this spring. Wouldn't have it any other way!