Many volumes of the "Year's Best SF" anthology series are currently $0.99 each at Amazon (US).
Vol 1
Vol 2
Vol 3
Vol 4
Vol 5
Vol 6
Vol 7
Vol 8
Vol 9
Vol 11
EDIT: Price also good at
B&N,
Sony &
OmniLit. They are also eligible for the buy 10 get 1 free promo at OmniLit.