I use efax for everything right now.
www.efax.com I work out of my house now, and I originally called and had a landline set up to use only for fax(I don't have a landline here for phone, just use cell as phone), and efax set up at the same time.
Well, I never had someone come in and hook up the proper lines inside the house for the landline, so I've been using efax for the past 2 months. It's kind of a pain at first to send faxes, because you have to scan the document first, but I've got used to it, and it's not expensive.
Basically how it works is you get an assigned phone number to receive faxes, which go into your email inbox. To send a fax, you can either just click on any document on your computer and "send fax" or scan the physcial document and send it, and you get emailed notification if the fax was successful or not.
I'm still paying the phone bill that I never had fully hooked up, and I'm pretty sure I'm going to cancel it and rely soley on the computer fax.