There are lots of difference between a soldering station and a soldering iron. Usually, a soldering station cost some where between $50 to several hundred dollars. The soldering is a lot cheaper, usually under $20. So, what leads to such a price difference between a station and an iron? Let us find out.
1. One of the major difference is that with the soldering station, its output temperature is regulated through a feedback loop wile the the soldering iron puts out as much as it can. To achieve controlled output temperature, you need a temp sensor embedded close to the soldering tip. So, it can send the actual tip temp back to the station so that the station decide what to next, put out more heat or stop.
2. Another difference is that the soldering tip of the soldering station is grounded while that is not the case for soldering iron. Why you need that. Let us use diode as an example. With regular solder iron, when you solder, you may see the diode light up since the soldering iron actually power the diode via its tip. This is potential over-stress the device. Not only that, in the winter, the air is very dry. Human body usually is charged up. When one solders, the finger may accidentally touch the device to discharge those charge. That may also destroy the device. It is called ESD damage. But, all of these are no problem for soldering station since its tip is grounded. During the soldering process, it will not power the component.
3. Auto off function is available with almost all the soldering station, I have not seen one without it. Usually, when you do not use the soldering station for a while, it will automatically turn off. This is very useful. Leave the hot iron on is never a fun idea.
4. Power cord, usually for the soldering station is not burnable. The hot tip touches the cord. The cord stay intact. But, with regular soldering iron. It is very bad to touch the cord with the hot tip. It burns and the burned plastic release toxic. You do not want to breathe those into your lung.
These are the major difference between soldering station and soldering iron. If you want to know more, you can check out some the wiki page. That should be very helpful.