Legal Question in Business Law in Massachusetts

You should contact the lottery to determine whether it recognises such agreements. I beleive it does, but you should find out what conditions if any (such as writing) that it requires in order for it to recognize it. Regardless, even if not recognized by the lottery the agreement will be enforcible among yourselves. I see no reason why it would have to be in writing. However, if there is a big win, people can change and a dispute could arise. It is probably a good idea to set out the terms of the arrangement on paper and keep a list of every one who pays for that week. Issues that could arise if there is a big winner: what happens if the person who buys the tickets also buys some for himself and claims that was the winning ticket and how are you certain that a certain person paid that week. I don't think you need a formal contract but you should set forth the arrangment on paper, have everyone agree, and then, every week, somehow keep track of the tickets purchased and the people who paid. Again, the first thing I would do is to contact the lottery.