Nuts with nylon inserts

I have replaced the struts and upper control arms on my 2003 Crown Victoria. The Ford service manual says to discard the nuts that hold the control arm and the nut that fastens the bottom of the strut to the lower control arm. Are these nuts a dealer item? Or is there a less expensive place to buy them? Is reusing the nuts so bad?

You should replace them as they are a Nylon style lock nut. Nylon Lock Nuts are really only a one time use. You should be able to get an all metal lock nut that will work at O'Rielley or Autozone that is where I found mine when working on the pitman arm.