I would say the trident V2 it is in that price range.Do not get the Igo-W V2,V3,or V4.All I have seen and read are bad things about these
rda's.
The EHPRO Helios also falls into the price range and has good
reviews it is the closest clone to the original.
These two would be my choices for the price range you have posted with very good adjustable airflow.I do not have the clones but I do have the original Helios and it was worth the money I spent on it,well worth the money.