Mercury Dime Set

Apparently no one else wanted to welcome you so I'll do it for all. Actually you already got most of the possible answers. Asking someone a question as vague as that is like asking how much is my car worth without any info except it is in good condition.
And what makes it even more difficult is how some would say this coin is a G-4 and someone else would say it's a F-12.
There are many price guides on the internet. I just downloaded one for Mercury dimes from the NGC web site on coin prices. Numismedia and PCGS also have such price listings. Just to give you an idea of price variations, in the NGC listing for Mercury dimes they go from G-4 @ $820 to MS67 @ $44,850. Since this is only a guide, those prices are really also flexible. The 21 could run up to as much as $20,000 in MS-67.
Other questions so far not asked is what kind of Album or Folder are they in? Are they all in 2x2's? All in a jar? Odd no 43's, 44's or 45's. Did you check for those 42/41 and the 42D/41?
Now back to the grades.

Exactly what do you mean by Fine to ExFine?
Such a set could run from a few thousand to almost a hundred thousand based on condition.