You can send faxes from the Academic Technology Commons (ATC) on the first floor of the library. There's no charge for it, the machine is available any time the library is open*, and it's simple to do. The fax machine is in the ATC print lab (where posters are printed), and the instructions are posted directly above the machine.
(*NOTE: When the print lab is unstaffed - weekdays before 9 a.m. or after 6 p.m., or on weekends, you will have to ask a library staff member to accompany you to the fax machine.)