The Small Motto 1864 and the 1872 in the 2-cent series are fairly expensive and the 1873 is a really expensive proof only. All the others are readily available and relatively inexpensive. In the 3-cent series, the only hard ones (read expensive) are the nickel 1880, and 1882 through 1887. And the silver 1883 through 1872. None of these are hard to find.
I agree with davidh. Most dealers would have a good number of them. But, once again, the set won't run cheap.
Lots of toughies in there. But, as for the small motto, you may be able to cherrypick it. I have, about 3 times.
Two more toughies in the nickel three cent that Davidh didn't mention are the 1877 and 78 proof only issues. You can toss the 1879 in with the tough pieces as well. Not as expensive (but not cheap) but tough to locate.
