There is a very wide price range between the different metal beds, but quality should be considered when buying because the bed should serve its purpose for a long time. New metal beds are available for as little as €50, with no upper limits.
There are also metal beds for over 2,600 €. Most metal beds are in the mid-range segment between about €200 and €600, depending on where you look. There is also the possibility to buy used metal beds.
You can also have your metal bed made to measure, so that it fits your wishes and ideas. However, you should be aware that a custom-made bed can cost a lot more money than other metal beds.