us3rnotfound ,
Two more points to add to what Ken90630 said.
1) If you're using DSL service to access the internet, you can run a fax machine, and the telephone handset attached to it, off the same phone line as, and simultaneously with, your computer. You just plug a "Y" into the DSL line's wall jack, with one leg to your computer, the other leg to your fax/phone handset. In my case, Verizon automatically supplied 4 of those "Y" connectors free with the DSL service. Or you can buy them cheap. So you don't need to pay for a separate phone line for your fax.
2) If you have a dial-up modem in your computer, and are running Windows XP, you don't need to buy a fax machine. You can just use the fax "machine" built-into Windows XP.
Start \ Control Panel \ Add or Remove Programs \ Add/Remove Windows Components \ check Windows Fax Service. It works great for both send & receive!
Three things about that:
(a) Some of the fax drivers may be missing from your Windows XP installation disk. When I activated Windows Fax Service, it wouldn't install itself properly until I Googled some of the required driver files from other places on the web, and
(b) if you have a DSL line into your computer, then each time you use the fax you have to move the phone line where it plugs into the back of your computer, from the LAN port to the modem card port. But that's easy to do, just takes a second, and
(c) You need some sort of scanning capability to enter documents into your computer for faxing. Perhaps your printer has a scanner?
So this might save you around $200 on a fax machine, a technological dinosaur. For the occasional fax, all you need is a $30 modem card. Another benefit is that the quality of what you fax directly out of your computer is higher than if a fax machine has to scan it in before sending.
EDIT: It just occured to me that it should work to connect a "Y" into the DSL phone line port out of your wall. Connect 1 side of the "Y" to your DSL modem and on into your computer's LAN port, and to connect the other side of the "Y" directly into your modem card's port, bypassing the DSL modem. Then you'd just leave it set up like that, no need to move the phone wire between ports for each fax use.