If the selling rate exceeds buying rate, the selling cell background colour will have green. Make sure Col A & C will have the same products and Col A & B relevant Col. If Col A cells match on Col C cells, then Col D cells will have green based on Col B cells.

I have tried: =NOT(ISERROR(VLOOKUP($A1,$C$1:$C$1000,1,FALSE)))

But it's not working as i have expected.