Maybe some of you DIY folks could answer something that I've been wondering about. A lot of ejuice is sold in the $20+ range for 15ml compared to other suppliers selling it in the $5 to $12 range. Having tried both premium (expensive) juice and the cheaper stuff I have noticed a difference in quality. The components in juice VG, flavorings, and nic (I avoid PG) is pretty simple, and I would think, not have the options of too many quality variances, but obviously they do. Can anyone tell me what it is (are?) that changes from premium to cheap juice that makes the difference in quality and how much of a cost factor that is to the overall cost of a bottle of juice?