Given the Lakers are in the same division as Sac, you'd have to think they'd need to pay a premium to get him. I'm sure Sac would rather accept a similar package from the East.
It's important to remember that trades are not always about demand in the market. There is a floor for how much a superstar is worth, nearing the end of his contract doesn't decrease that floor.
The least we'd ever have to pay is something like:
Cousins for Amir, Smart, Nets 17, Mem 19
or
Cousins and Barnes for Amir, Rozier, Young, Nets 17
Likely though we'd need to include both Nets picks + Smart/Rozier and Amir to get it done. I don't think we'd want to do more than that, that's already a huge package