Bikesharing services are always a bit extortionary in their daily pricing, sometimes nearly $10 for a day pass. Hubway was reasonable on a yearly pass for $85 as taking care of your bike would cost about that much.
As of April 22, 2017 Hubway is increasing yearly pass price to $99 from $85. Monthly and daily passes seem to be staying at their previous price of $20/month and $6/day. Always remember to check if you have an employer-based Hubway discount–it can be quite substantial.