A few years ago I tried to find the best internet fax  options and came away with few options that impressed me. Fast forward a few years and of the companies I listed on that page, the only I still use is FaxZero .
What do you get? You can send 2 faxes a day of up to three pages as long as you’re OK with the first page, which isn’t counted, has an advertisement on it (it’s just the FaxZero logo, but I imagine it could be anything). You can send something as long as it’s a Word doc or a PDF, I’ve just always scanned the document to a PDF and sent it like that.
When you send the fax, you have to enter a valid email address. They send you an email with a link that you must click before they send the fax, this is probably to cut down on junk faxes (that and the limit). The email they send comes in about a minute or less but it could take longer.
I’ve sent maybe a dozen faxes this way over the years (who uses fax machines these days anyway?) and it’s worked like a charm each time. I imagine this wouldn’t be all that great for professional use but in most cases my recipient didn’t care that the first page had a huge FaxZero logo on it. They also have a pay version for $1.99 per fax which has a limit of 15 pages and no advertisement on the first page, for those cases where the first page ad would matter.
Do you know of any better free faxing services?