How long can you stay @ the park and what does it cost to stay like a month?

You can stay up to 14 days at a time - the full rates and regulations are here: https://www.iowadnr.gov/Places-to-Go/State-Parks/Make-a-Reservation/Overnight-Camping

Stop by the office and ask to make sure.

At the moment its 15 a night and 105 a week, but prices change and also depends on availability.

I'm sorry was driving by and didn't see anything posted.