What business involving fishing/ boating could I start for less than $

Wow, that is a tough one.   With the charter and fishing industry hurting with fuel prices, a bad economy and fisheries restrictions, overall the industry has been hurting.  Plus it takes a fairly good amount of money to get into the business.   Trying to make a go of it part time is the most difficult.

I myself am retired and do the charter business but it would never provide enough income if I was not retired.  No one in the business does chartering to become rich.