Some Boston hotels are definitely better than others, but they are all expensive these days.  There is a shortage of hotel rooms in the city, and it will probably be a year of more before enough new hotels open up to normalize the price.  It is a fortune to park in the city as well.

A lot of girls who visit the area choose hotels in suburbs like Braintree, Woburn and Waltham where the rooms are much more affordable and it's free to park.  The downside is that you don't have access to all the entertainment and foot etc... like in Boston and you have to be more careful about LE.

If you do choose to stay in the city, I would recommend the Copley Square area.