Maverick,
When you say family of four it depends on how old they are and such and if you are looking for family fun or beach relaxation and such. If the kids were old enough(maybe high school or eight grade if a boy) and you and the wife are fairly active you could consider a great number of things that are far more affordable. Just need a bit more info and I am sure I can help you out. Is there a spending and/or length of stay limit? Do you all have passports? I would also consider places other than Mexico that are equally as economical and very nice. You may consider the Pacific Northwest, or a canoing trip in Canada, there is a very economical resort in the middle of the rain forests of Costa Rica called the Tabacun that is nice. There are several options, just need you to narrow the field for me.