Is there any cheap places for a family with 8 children to move to in the state of Quintana Roo Mexico?

[tenhearttkc]

We are looking to move to mexico in 2 years. Our income will come from the US and will be about $4000 a month. Does this seem to be a reasonable amount to live on? We will either homeschool or send the children to private school. We would like to move with in an hour of the beach and want to live near a small village but not far from a city, somewhere in the state of Quintana Roo. Can anyone give me advice on this topic?
Would $4000 a month be enough to support a comfortable but conservative lifestyle for a couple with eight children? We are NOT into material possesions but we love to travel an experience new things.