1871-1874 CC dimes (1874 CC retails around 10K) 1870-1873 CC quarters (1870 CC retails for 10k) 1870,1878 CC halves (1870 is the key) 1878 CC trade 1870-1873 Seated trade dollar (1873 brings 5k, 1871-1873 are scarce) All are very scarce, and hard to find. Usually sell over asking. Also gold CC's are highly desirable as well
As a whole, CC Morgans are far from rare... they are popular and that is a huge difference. There are certain dime/quarter/half dates that can be had cheaply (especially in low grades), but as the other guy said, some can be quite pricey. The same with Carson gold... there are a number of double eagles that one can buy for rather small premiums. The 1891 $5 and $10 are plentiful and can also be affordable when compared with other dates.