A Commerical Fishing license to set more than 5 traps and sell crayfish costs $111.75 for residents and $266.75 for nonresidents. You then must buy a tag for each trap that costs $3.
Note: Commercial Fishing license are on a fiscal year rather than other IDFG licenses that are issued on a calendar year. Commercial licenses are good from July 1 through June 30 of the following year (e.g. a license purchased after July 1, 2013 is valid until June 30, 2014).