RIT liquid dye is good for dyeing nylon net, not sure about polyester net. You can spray net using car spray paint, Plastikote, or Rustoleum paints. If dyeing, look at the RIT website where they have formulae for 500+ colours. Some colours work better than others, pinks are fine, Teal was OK but I found getting a good Royal blue a bit difficult.
It's actually a lot of fun experimenting