Intravee is £120 brand new...
http://www.toysinyourcar.com/acatalog/intravee.html
Alpine KCA-420i between £25 and £45 on Ebay regularly...
http://www.ebay.co.uk/itm/Alpine-KCA-420i-iPod-interface-/182109108053?hash=item2a668c7755:g:Ah4AAOSwGotWpKht
http://www.ebay.co.uk/itm/ALPINE-KCA-420i-FULL-SPEED-IPOD-ADAPTOR-FOR-AiNET-HEAD-UNIT-IN-CD-CHANGER-SOCKET-/111982459727?hash=item1a12acbb4f:g:gIgAAOSw8d9U0lXO