Update: Looks like this free service is no longer available.
Corissa sent me this email about how she got a free phone number:
I saw one of your readers was wary of giving out her phone number. I wanted to tell you about what we do. My husband set up a free VOIP (voice over IP) phone number with www.talkdigits.com. He set it up about a year ago, and it has always been completely free for us. (The “catch” is it costs to CALL OUT with this phone number.) This is the number I give out to any online forms or stores that want my phone number, or any other time I want to use a “junk” phone number. It is nice because, besides being free, you can set it up to ring on your computer OR, what we do, have the calls go directly to voicemail and then send you an email with the voicemail as an mp3. Then if someone actually needs to get in touch with me, I can hear what they have to say and call them back.
Thanks for sharing this great tip, Corissa! Money Saving Mom also mentioned Skype as an affordable phone service alternative.
Update: Same deal here with Skype, the free phone service no longer exists!