Every once in a while I stumble on to a new tool. This one found me when I was looking to use a neighbors fax machine to send a video production estimate. (yes in the digital age - when we are making digital videos - production estimates still go via fax) The neighbor was not home - and the B&E charge simply was not worth it. A quick google search uncovered HelloFax. Yes! Rage against the machine! HelloFax is a great tool.
You can use your browser to send free faxes sans machine: just enter a phone number, upload a doc (PDFs, JPEGs, etc.), and HF'll deliver it to your desired destination, which, considering it's a fax machine, is probably somewhere the 1990s.