Very few managers are interested in 3-4 starts players because they are noobs and don't know what to look at to find a good player.
The lower stats and higher price a player have the better and bigger talent is he and you can get 3-4 points for doing all 3 trainings per day.
I only buy players that is worth a lot and have low skills. I never buy a 6 star player that is worth 560k even if he is 18 years old i rather buy a 3 star that is worth 2 mill. Because my player will catch him up much faster and it is easier to train special talents on them since they active so many tailings point for games and trainings. A 6 star player worth around 600-800k will barley get 1 point if you do all trainings on level 3