Whatever price you find, make sure you are getting the full manufacturer's warranty, in writing -- this should be 3 Years, or 5 years from Seagate and 5 years on the Maxtor MacLine pro series drives.
You do not want a Pull, Recertified, Reconditioned, B-Stock, NOS (New Old Stock) or other drive that has zero to 1 year warranty. You also do not want any equipment that says "warranty covered by seller" or "Warranty from importer" because that is a tipoff that these are grey market goods that do not have any coverage from the manufacturer.