None of the costs above take into account any extra bundled software. It is up to you to assess the value of any included software, joysticks, etc.
Update 2022:
Recent prices went up: A good refurbished 464 goes for €90-150 on ebay (without Monitor or Diskdrive). A 6128 you can get around the same price. There are a lot of offerings that try to sell 464 or 6128 with monitor (mostly green monitor) for 250+€.
====Things To Look Out For ====