I acquired an eFax telephone number several years ago for inbound faxing.  I think the area code for my eFax telephone number is in Utah somewhere, however for inbound faxing, the service has always worked well.  For outbound faxing, eFax has always required a monthly fee.  I have recently discovered www.pamfax.biz for outbound faxing.  One can conduct on-demand outbound faxing without needing to pay a monthly fee.   Pamfax can also use your Skype credits for payment. 

Cost per page is only about 15 cents per page, and Pamfax works well with sending PDF documents.  One simply uploads the documents to be faxed and selects and fills in a fax cover page.