Cancun has always been less expensive than our trips to either Vegas or NYC. And if you want a drinking age of 18, you ll have to leave the country. Maybe you can look into the Bahamas? Or another Mexican resort - Cozumel, Los Cabos, etc.
As long as you aren t going in winter, you could go to Montreal or Toronto.Cancun shouldn t be expensive - I don t know where you are looking, but there are a lot of discounts on hotels there, especially with the economy the way it is. Also in Mexico, Playa del Carmen is a lot nicer than Cancun - Cancun has huge hotels that are spread out, while Playa is a town right near the beach and is walkable. You fly into Cancun, and it s a 1 hour bus ride.Dominican Republic is also cheap.
Drinking age at 18 would be the midwest not the west