I don't believe that there should be a minimum price for alcohol, because if it is too low I think it might tempt some to purchase more than they ordinarily would. I also believe that if alcohol was less expensive it would make it more accessible to kids that are underage.
If there is a minimum price then people will want to get their dollar's worth so they will drink greater amounts of liquor and other high-alcohol alcohols. In fact it might get to the point where light alcohol drinks aren't even made available because they aren't selling. This is a bad idea.
There should not be a minimum price for alcohol. There should not be a maximum price either. Supply and demand always works so it should be no different when alcohol is involved. If people are willing to buy it you have set a decent price. If they are not you might want to consider lowering.