A vaporizer is a device which heats up dried herbs to a temperature at which they release their (medically) active components into an aromatic vapor. This vapor doesn't contain any of the toxic elements found in smoke.
Yes, there is no doubt about that. We believe that with the advent of the vaporizer, smoking will soon be a thing of the past.
Some heating elements might be safer or more stable than others. To learn more about the different heating elements, read Types of vaporizers.
Conduction refers to heating herbs by direct contact, whereas convection refers to heating them with a flow of hot air.
When medicinal plants are vaporized and inhaled, this process is generally referred to as phyto-inhalation rather than aromatherapy. An extensive list of herbs that can be vaporized can be found in this vaporizing temperatures table.
A vaporizer might be expensive because of the materials used (borosilicate glass, metal, heat resistant plastic etc.), the technique employed (type of heating element, analogue or digital temperature control etc.) or both. A good vaporizer doesn't have to be expensive, and an expensive vaporizer isn't necessarily better. But if you're looking for a device that lasts long and can be used comfortably, buying one of the cheapest vaporizers will likely be disappointing.
If you already have a (small) glass bong or an iron pipe, you can easily transform it into a vaporizer with the Vaporstar or the Vapo-bowl respectively. It's also possible to make a very simple vaporizer from a light bulb, or even to make a whip convection vaporizer, although especially the latter may not be that safe. We do not recommend building your own vaporizer with a heat gun (like a hot air paint stripper), because such heat sources were made for industrial purposes, not for inhalation.
Generally not, but this depends on the type of vaporizer. For some models emptying and refilling the herb chamber or cleaning the vaporizer might be a bit bothersome. One must always be careful, as the heating element and the filling chamber can get very (very!) hot.
Again, this depends on the type of vaporizer. The Volcano requires hardly any cleaning, whereas portable glass vaporizers usually require a frequent cleansing with hot water or solvents.
It is likely that you're vaporizing at a temperature too high. Though it can be nice to inhale very concentrated white vapor (because of the strong effect), it is difficult to keep this in the lungs. Lower the temperature and the coughing will likely cease.