Got both Hard and Ultimate challenges planned out. Don't think they can be done much cheaper either. Will just have to spend the first couple of weeks of Fifa 17 getting them all up to 10 chem!
for players like us, the sbc is like a dream, i play with unpopular players as you do play - many times, and by those, we can exchange them to challenges when we play like 10 games, i/o forcing them to sell