Most Alaska charters charge a per person rate. A goggle search and a few phone calls should tell you the information you want
I would suspect a half day trip would run 300-350 and a full day in the $500 range
That's pretty much been my experience on Kodiak.
Most charters on Kodiak are full day. Half day charters take too much travel time for the full day fares.
Last time on Kodiak, 3 days was $1200.
Figure in processing, lodging, meals, airline tickets and tips and you'll spend between $4500 and $5500. ....and that's doing the trip "on the cheap"! LOL!
The halibut are fun, but I'd rather have a box full of P cod!