Four agreements, accounting for eight licenses, include substantial payments on top of the 3 percent: Alternative Therapies Group in Amesbury will pay an extra $25,000 annually to charity; I.N.S.A. Inc. paid Easthampton an additional $10,000 upon signing; New England Treatment Access will pay Northampton another $10,000 annually for “marijuana education and prevention programs,” and in Brookline,it will give a further $25,000 annually to a drug-related nonprofit chosen by the town.