If you get a local cell plan, it'll be either $17-19, call unlimited locally. $5 with all the "taxes" charges, etc.. IS NOT worth it. You couldn't even use a calling card on it, which I can use on a cell.
I've got a $7/mo local plan from Verizon with my DSL service, like the one described here for $10. Funny, I just got a telemarketer call for home financial services right after I started this post, those have been very infrequent with the "Do Not Call" registry. It's kind of useless, but its a cheap option for the alarm system.
With the fees/taxes, its been about $15/mo for the phone line.