Suppress #NA errors for a cleaner look

Try wrapping your formula in IFERROR()
=IFERROR(your-formula)

OR, just test to see if the input cell is empty...
=IF(inputcell="","",formula)

The second one got it; the first just blanked the result regardless of the input. Thanks!

EDIT: No such luck. It looked good but broke the minute I tried to input a real value.
This is what I tried: =IF(F6="","",(VLOOKUP(H6,AA6:AB9,2,FALSE) + 12.5))

It blanks the result cell if there is nothing in the drop-down input (as I want it to), but if there's an actual valid input it doesn't work.

hmm the IFERROR will only activate if there is an error, so there must have been an error to begin with?

Anyway, Im happy you got this resolved

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Using your example worksheet, test for contents in column A. If the cell in column A is blank, the formula returns a blank cell. You could use any other column that could have a blank cell like column D. Either would work.
Try this in G2 and fill down

Formula:

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	A	B	C	D	E	F	G	H
1	CALL	NAME	City/State	QTY	New member Y/N	Fastener Type (use arrow for dropdown list)	Badge Cost	Your Cost (including fastener)
2	KD2FSH	Gerald	Fairfield, NJ	1	Y	Magnetic (add $2.50)	$15.00	$0.00
3	K2AZ	John	Seattle, WA	1	N	Magnetic (add $2.50)	$15.00	$15.00
4	AA2NI	Niko	Tenafly, NJ	1	N	Magnetic (add $2.50)	$15.00	$15.00
5	KF2TI	Steven	Landing, NJ	1	N	Magnetic (add $2.50)	$15.00	$15.00
6
7
8

Maybe this?

Formula:

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try this...
=IF($F6="","",VLOOKUP(F6,Y6:Z9,2,FALSE)+12.5)

Just tried AlKey's suggestion, and that worked too (as it should have)
=IF($A6="","",VLOOKUP(F6,Y6:Z9,2,FALSE)+12.5)

Also, you need to absolute that range so it doesnt change...
=IF(F2="","",VLOOKUP(F2,$Y$2:$Z$5,2,FALSE)+12.5*D2)

No, none of this is working; something on the sheet is now broken because for any value used in column D there is nothing resulting in columns G or H.

The result for column G is to take the sum of $12.50 added to the extra costs from column F, depending on what the user selects. Column H is dependent upon column E's result (new members can have one free badge but must pay for the others).

EDIT: I like the idea of making column A the conditional for display/no-display, but anything before the VLOOKUP seems to break the entire formula.

Here is your file with the suggested changes made

Good stuff, happy to help and thanks for the feedback

Out of interest, what was happening that the suggestions did not work?

haha ok, I hear you. Happy you got it resolved