=IF( Question - Tough one, pretty convoluted

wow why is it necessary to use all those merged cells? We all hate them here and advise avoiding them if at all possible - they cause all sorts of problems with formulas/sorting/macros etc.
I did a quick scan of your sheet and can see no valid reason to use them - if you need wider cells to show stuff, just make the column wider

OK picking through your formula....
you are testing for....
AND(AR3="",AR3<0,CD3="",CG3="")
if all are met, "", however, both CD and CG are not "", so it goes on to the next test, which is...
IF(AR3>0,...then do a bunch more tests.

However, AR3 is <0, so all those tests fail.
Excel does not know what to do next, so it returns FALSE

You need to work on that 1st IF/AND statement to cater for when CD and/or CG are not empty

I simplified your formula a bit too, to do away with the repetitive test for AR3>0...
=IF(AND(AR3="",AR3<0,CD3="",CG3=""),"",
IF(AR3>0,
IF(AW3={"Plug","bolt","studs","EXPMETAL"},AR3*CG3,
IF(AW3={"Angle","Bar","WF","Channel","Hss","Pipe","Plate"},CD3*CG3,
IF(AW3={"REBAR","ALLTHRD"},BQ3*CG3,IF(AW3={"decking","grating","expmetal"},BY3*CG3,""))))))
So you need to just work on that 1st line (bolded)

Originally Posted by DGARDNERMAN

Hey thanks, for the kick in the teeth I presume.
I will undoubtably admit my intelligence is likely not as developed as other members, but I still like coming to the group when I have questions.
IDK...maybe I took your reply wrong, I apologize if I did.

aplogies, was not meant as a put-down, I can see now how that might have come across that way

OK just saw a logic error in the 1st part. You cannot use AND, you need to use OR.
AND(AR3="",AR3<0
AR3 cannot be both "" AND <0, so maybe...
=IF(OR(AR3="",AR3<0...
then (and I think you picked up on this), do you really need to test for ,CD3="",CG3=""?
If not, then perhaps...
=IF(OR(AR3="",AR3<0),"",
IF(AR3>0,
IF(AW3={"Plug","bolt","studs","EXPMETAL"},AR3*CG3,
IF(AW3={"Angle","Bar","WF","Channel","Hss","Pipe","Plate"},CD3*CG3,
IF(AW3={"REBAR","ALLTHRD"},BQ3*CG3,IF(AW3={"decking","grating","expmetal"},BY3*CG3,""))))))

With complex formulas like that, I like to try and keep things "paragraphed" to make the logic easier to see. To do this, use ALT ENTER where you want to start a new line