Guys thanks for the suggests... I spoke to Decameron directly today! It's definitely the cheapest.
I do got my Padi Open Water and I might do a couple dives but i'm definitely more interested in just gettin out of town with my wife for a few nights and you really can't beat San Andres due to the price.
note... wife is colombian so it makes it hard to travel to different places. We were gonna go to Cancun to meet my brothers and it's almost the same price as San Andres. But she needs a visa and since her papers are only in "process" the Mexican Embassy said they won't give her a visa.