If it's Tracphone I know you can buy airtime using cash and leave no "track" that can come back to bite you.  Cash is king.

Inspired a bit by this post: http://theeroticreview.com/discussion_boards/viewmsg.asp?MessageID=95202&boardID=33&page=#95202

I have been using temporary visa cards paid for in cash to get airtime. It is a little bit of a hassle though since cards like vanilla visa are becoming harder and harder to get in my area. I'm starting to wonder if its an unnecessary overhead and if I'm just being overly paranoid. I have a regular bank card that I would be okay with using under the assumption that doing so isn't that incredibly stupid. So I'd appreciate a sanity check from you all thanks!

Just ignore them & buy your cards with cash at WM, or your favorite convenience store, with cash.  If you buy a coffee or other small purchase, it's totally natural to use pocket cash.  You can add the minutes most easily directly through the center menu "prepaid".  
H

I bought the phone without divulging any personal info.  I top up my minutes by going into any Radio Shack and buying a $20 top up for cash.  The receipt has a PIN code you enter into the phone to put  the new minutes into the account.

phone with cash, activiated it on a public computer (library) and buy a $20 top-up card every 3 months for cash.  No trail of any kind.