Is it worth the time money and effort? will it do any harm?
or can it only increase hits?
I am new so forgive my ignorance
Thanks for any input
Okay, we've established that you will use all domains. It sounds like you want to create these sites purely and simply to link to a common site.
I would suggest you take each domain, create a different site with good content ... as I sait earlier - Content is king, make sure you have good keyword weighted copy, pay attention to your title and description ensuring each is different per domain.
By all means interlink them but your original idea isn't a good route.