I have never had as much trouble as I've had since Nikki returned Skipping Stone to Narragansett Bay finding any affordable slip, let alone a liveaboard slip. The closest I've come was arriving in Auckland, NZ and being told there were no public slips at all. So I took my 65' ketch and cruised the slips until I found a slip with filthy dock lines. I contacted the owner who said he was having a new boat and I could spend as much time there as I wished, for free!
You can't even do that here because any temporarily empty slip is rented to a transient. 12 years back I found a very inexpensive liveaboard slip in East Providence, but no more.
You might contact Consolidated Yachts Inc, City Island, NY.. When I bought Skipping Stone there (2009), it was a poorly run operation that allowed liveaboards but with huge metal pilings, it was pretty noisy when the wind was up.
Sorry I can't be of more help, but the slip situation here is a lot of why we sold Skipping Stone.