IF Statement Comparing 2 ISNA Statements

Hello!
I'll make this question short and sweet!

In N10 I have this:

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S24 is referencing a VLOOKUP that is determined by the drop-down choice in L10. Now, depending on what is chosen elsewhere, the choice in L10 needs to produce different results, which is reflected in S42.
All I want to do is produce an IF statement displaying the results of S24 OR S42, depending on which one is NOT displaying N/A.

Is this possible?

Try

=IF(ISNA(S24),IF(ISNA(S42),"Both NA",S42),S24)

Thanks so much for the quick responses!

What if BOTH cells are not displaying #N/A?

What type of data does the lookup formula return? Is it text? Numeric? Could be either? Something else?

Both cannot display #N/A, I have prevented that. They are numeric (dollar) values only. I'll give a brief example of what I'm trying to do.
In L10 there is a drop down of various data usages (300MB,2GB,4GB,etc). If I choose 2GB then S24 (which is in a hidden column) will calculate $60. HOWEVER, if K24 or K25 has a certain option chosen THEN S24 goes blank due to this:

=IF(OR(K25="CD Only",K24="Tablet Only"),"",VLOOKUP(L10,$R$2:$S$17,2,FALSE))

Once that goes blank, S42 is now active:

=IF(OR(K25="CD Only",K24="Tablet Only"),VLOOKUP(L10,$R$27:$S$40,2,FALSE),"")

If I choose "Tablet Only" in K25, 2GB now is worth $20, and S42 will reflect that.
I want N10 to show whichever cell has a value. If one is N/A and the other is blank (i.e. nothing chosen from L10) then N10 remains blank.

=IF(ISNA(S24),IF(ISNA(S42),"Both NA",S42),S24)

Unfortunately this doesn't show me anything if S42 is the active cell.

YES!
That was exactly what I needed, thank you so much Tony!

Try

=LOOKUP(9.99999999999999E+307,CHOOSE({1,2},S24,S42))