New York Governor Andrew Cuomo's proposal to give middle-class students free tuition at state colleges has touched off a broader debate about the cost of an education - and several alternative proposals.State Senate Democrats on Monday offered their own plan, which would make tuition free for students from families earning up to $150,000, compared to Cuomo's $125,000 threshold.The new proposal would also give lower income students more help with room and board and $10 million in increased aid for students at private colleges.The Democratic governor's proposal has been criticized for not addressing rising room and board costs, and for providing no new aid to poor students.Some type of plan is expected to be included in the state budget now being negotiated by Cuomo and state lawmakers.