For salvia, you'll want something that doesn't use a bag system. It doesn't sound like you're willing to spend much money on something terribly accurate or reliable, as long as it gets the job done. I'd say go with any whip style you can find that works best for you... although i'd stay away from the globe-style. My personal reccomendation for whip style with the best control, reliability, and limited surface area would have to be AroMed. Best medical equipment purchase ever. Volcanoes are the industry "standard", and do work quite well, but bag systems are not my personal preference.