Depending on your soil you can use nutes or just water. I know with the recipe that I will be using I shouldn't have to add anything but water until about 3 weeks into flower.
You don't have to go with FFOF but that would be a good start.
Soil is something you just can't skimp on im my opinion. If you do you are just going to be chasing issues all season and spend more money on nutes.
Keep in mind you can do anything you want and this is just my opinion.
Don't take anything anyone says as gospel. Research what they are telling you and see if it's something you want to do.