PPR Trade Help Thx :)

I have too much depth on my team imo and would like to trade some of that depth away to get a star player. My main target is gurley as the rest of the gurley owners team is straight garb, and he has expressed interest on selling gurley to fix his team. Basically would like to know how much to give up without overpaying… His original offer was Mixon, McKinnon, and Evans for Gurley
–My Boys–
QB- Goff, Taylor
RB- Bell, Howard, McKinnon, Mixon, Mack, Lynch
WR- Thomas, Tate, Evans, Parker
TE- Kelce, ASJ
(Full PPR 1QB 2RB 2WR 1TE 1FLEX)

Personally believe that’s way to much for Gurely. You already have 3 RBs who could easily by all RB 1. If anything you should possibly go after a better WR