They might seem a bit pricey for what it is, but they operate on a "buy one, give one" model, so it's a pretty good deal considering that. They make a great gift for anyone in your life who needs more iron in their diet.
If you live in a developed country, you don't need one. There is iron in a wide range of common foods, both naturally-occurring and artificially-enriched. "lucky iron" fish are useful for people living on subsistence diets.