Shopping around for Cosequin for my cat

In was $30 for a white plastic bottle of 60 doses from a big pet store down in Concord.  It is $18  for an envelope of 84 doses of a product called Dasuquin from my vet in Whitefield.  Whitefield Animal Hospital on Rt 3, right on the steep grade on Rt 3 going north out of town.  It is still doing my cat good, she goes outside more often, can jump up on furniture that she hasn't been able to manage for years, less limping as she slinks around the house.