AirportHobo

Can someone help me find this manga? Its about this dude reincarnating into an extra of a novel/game (I cant remember what) from his original life. The original novel/game was a romance story between a prince and a girl, but he is already engaged and blah blah. In that world, women are in higher positions than men and he is at risk of being in a forced marriage with an old woman. In order to escape that, he finds this ship thing that the hero is supposed to get in the regular story later and tries to become rich?? So basically stuff happens and then he goes to the school that the main characters are and he tries to get money. I cant remember much of what happened but i remember later that the girl who was originally engaged to the prince is in trouble or something and he helps her and the prince challenges him to this robot(?) fight. The characters go inside a huge robot/armor thing and fight and the guy beats the prince and four of his friends(they all like the girl that the prince likes).