blueyedbabe said "Do you know how much it is? I assume you can just walk in with your own balloons and ask them to fill a couple? Thanks for the info! "
Loonies Too a has limited helium and won't fill any beyond the orders they have. You can't take your own balloons there.
Apparently South end Sobeys has lots of helium. Not sure if you can bring in your own balloons.