Well think about it, when a lighter makes contact with flower it turns charred while if a vaporizer set to a temperature which won't create charring but rather a bit of browned bud, more of the THC content is conserved when vaporizing. Lighters create flames significantly hotter than the heating element of a vaporizer and this is wasteful to bud.. It's science.
I've heard of a great, cheap bag vaporizer involving components of a variable temperature heat gun and a couple components from the volcano (attachment and bag), that worked quite well. But this is what I use, a vapor brothers desktop vape, was $125 for the blemished handheld model:
https://www.google.com/search?q=vapor+brothers+desktop+vape&espv=2&biw=2133&bih=1061&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjHkYKlvNjLAhVS7mMKHTYVB40Q_AUIBygC&dpr=0.9#imgrc=G4O-yXW7svhjCM: