The mint sold out of them early and quite a few people got caught before they had purchased theirs. It created an instant demand for the set and the price went up.
I think it's so high because it is the last year of the State Quarter program and the last year of the Lincoln memorial cent(LMC).. So that makes it a twofer which I and many others jumped for aquiring at least one set. It was hectic on the first day as I rember.