The cost of alfalfa seed averages $4 to $9 per pound, as of 2015. However, alfalfa seed generally costs less per pound when you buy in bulk. For example, HancockSeed.com sells 1-pound bags of seed for $9.50 and 5-pound bags for $28.99.
The alfalfa seed brand also affects price. For instance, Seedland.com offers 50-pound bags of its Bulldog alfalfa seed for $315 and 50-pound bags of Ameristand alfalfa seed for $384.
Price also varies among retailers. ElkMoundSeed.com offers low prices on 50-pound bags of alfalfa seed, including its SuperLac brand, which retails for $212 and its winter-hardy Lactator brand, which retails for $202.