I seen in Florida and other location they come with huge tanks and fill up new tank with already cycled water I wonder if that service is offered in the tristate area ny nj ct
These companies were likely delivering real ocean sourced saltwater that has some potential benefits, but instant cycling your tank is not one of them
The nitrifying bacteria that process ammonia largely populate surfaces such as your rock, sand, biomedia and more. There are relatively few of them just free in the water.
To instantly cycle a new tank one must use previously cycled bio media, which can included rock, sand, and plastic or ceramic biomedia. These media would have to come from a well matured aquarium for them to be populated with enough bacteria to instant-cycle the tank.
To hasten a cycle you can use at least 10%-50% (the more the better) real live rock/dry rock. You can use specifically Fritz TurboStart, which works quite quickly to make the tank safe for fish.