I use electronic fax for my business.
www.fax.com
I have been using them for over 3 years and love it.
Just $9.99 a month so it is less the phone line alone.
No extra phone line.
My own 1-800 fax number to give out to my customers.
No toner.
No machine.
In coming faxes are automatically emailed to everyone in my company that ever gets faxes.
To send a fax I just upload it to their website and click send. If I am faxing a signature then I just scan it and then upload it.
I believe they restrict the number of faxes or something for the $9.99 rate but I have never had an issue. I only send a few a month, and probably get about 20 or 30 a month.