DD - you forgot the two other parts for ancient Israel. A butt ugly hopeless case who even the fathers would refuse to sell to him would only have to rape the hottest virgin he could find then he would be forced to pay the going market rate for her and they'd be forced to marry.
Or the rich ones like Solomon, if they have wives, unlimited amount, they need to properly take care of them, housing, etc, but if finances were tight or if they were just cheap they could also claim concubines who let less benefits, etc.