Farm land cost in coastal tamilnadu

Dear All,
I am trying to understand the cost of land (farmland intended) along the coast (within 1km from shoreline) along the shores of tamilnadu. Could someone having relevant information please appraise me regarding the cost/acre along different districts? This is for information purpose (at the moment at least) and not with the intent of purchase of land.
In such soil (coastal alluvium/sand), what type of crops can be thought of? (Considering of course the possibility of sea water ingression (salinity), poor organic content of soil etc.)