Want to get a remote key and cut the key part off- just program the car for the remote (for a friend's 2010 Base Fit).

Will any Honda key work? I figure it's easier to find a used key if I don't have to specify which model it's from.

 

I got the first for my base from the local honda dealer and paid a silly amount.

The 2nd one I got from CFL Honda. Check this thread (free shipping, just say "Dan" sent you, don't know if it still applies though).

If $36 is OK, here's your key. (search part number 35111SWA306)

I got mine cut and the security programmed for an additional $60 at a local Honda service dept. But as you suggest, cutting off the key part you can program the remote entry yourself.

Sorry, I don't know about interchangeability with other Hondas.