I don't really see the need for a super expensive vaporizer/atomizer unit. There are many $10-50 units which atomize/vaporize medication and deliver it in steam effectively. In my opinion
, there are a few major concerns.
1) How often do you plan on using this?
2) Where will you be using this (portable? always at home? office?)
3) Which do you prefer, cold or warm steam?
First off, I would strongly suggest speaking to a pulmonoligist/respitory specialist if you haven't already done so. Then discuss the plan of action and specific medicinal/herbal product you want to try. You may have already done so, but I just want to state it again since inhaling atomized chemicals can be very dangerous.
I would try an inexpensive nebulizer or cheap evaporative vaporizer like this Vicks
. You'll need to find out what conditions your medicine/herbals need to be effective. Eucalyptus oil may need 190C to vaporize but I'm not sure that is what you want. In fact, you may not want that at all as it probably changes the chemical properties. You probably want atomization via sonic or sub boiling evaporative process. Also note that regardless of the process, all humidifier/vaporizer/nebulizer devices can spread germs so make sure you keep it well cleaned and follow care instructions.
I would try out something like what rezinn suggested. Also try it in small steps with advisement from a physician, especially if you have asthma.