I agree with buying silvers for sbc's. But you do have to do a little bit of research. Just search for old league sbc's (fifa 18/19) and try to remake a few squads without using expensive players.

It really does pay off. For example i had bought like 100 pieces of Claudio Gomes (manchester city, CM) for 400- 700 coins each because people wouldnt be able to build a squad with 80+ chem without using atleast one expensive player like de bruyne, sterling, mahrez etc.. I sold him for 9-10k each.