In the PNW. I don't know your area, but marinas/ports that cater to commercial fishing usually have cheaper rates. Often the docks aren't as nice, no babysitters, etc. Sometimes you can find a private dock, I usually do. Just paid a months dockage, $400 for an 83' boat. Electricity, no water (but I make my water), no internet, no laundry, but have that, too. In a yacht harbor I'd pay $800-1000 or more. About $500/month If I stay in a slip in a commercial port. One is $600, but free power, water and internet. Less expensive dockage is out there if you look and you're not fussy.
I can remember paying 50¢ foot, but that was long ago.