It looks like a child's pull toy. Is that gold or just a bad photo of a white horse?
I have not found one yet that stylistically resembles your horse...fat rear, arched skinny neck, stiff front legs. Is this a carved wood horse, hide covered, leather saddle, solid wheels, rectangular wood platform, etc.?
Depending on what he is made of, condition, and if all original, I would ball park it in the neighborhood of $1000 at least.