its not really a glitch well firstly when you're on the main menu go on a create player once you have created that player put his overall stats high (but not to high cause you want teams to actually afford that player)make him a decent rating around the 87 or so and then select his team that u want him to be in your career when hats all done go on manager mode career mode and remember to chose the same team that your created player is when you are creating your manager remember to put your squads on coustimesed squads when that is all finished go on your squad to actually see you got that player in your team if you do then advance until a club offers it will be quick depending on the age of that player etc.. i.e rating clubs will then offer you around 50 mill for that specific player accept the offer warning you can do this as many times as you want just make sure you create alot of players for your new team in carrer mode who are highly rated so u have more of a chance at selling them for a high price once finished selling all the player(s) then you will have money alot no matter what team you are

Thanks if you have any problems with it PM me back il be glad to help if you're stuck
oh yh and another thing you cant put that player on sell you have to wait only a bit so that clubs offer your player