It really is expensive for just this little piece of plastic, but it sure is helpful when you have an IHome with multiple different IPods. It protects your IPod or your IHome from breaking. If you bend the IPod on addicent, either one or both of the docks will be broken and this prevents that. It is cheap though, that all of the IHomes come with these inserts but the mini.
I have just one Ipod, the mini. It was not made for very long, and I had to quit using it when the standard headphone jack got dirty and made playback sound like a scratched record (still not sure how this happened). Having these adapters made it possible to use a dock to connect to speakers, and now I am enjoying all my old faves again! The information was always there, now I have a way to bypass the headphone jack and access it.