Need help with vaporizer purchase

Hi,
 
I'm new to this website and new to vaporizers and dont really know much about them. I need help buying the G-Pen vaporizer. I know I definitely want to get the original G-Tank and the Herbal Tank, but I don't no much about the purposes of the essential oils and Glass tank are and whether I will need them or their benefits and differences the other tanks Grenco Science sells? 
 
I looking to use the vaporizer for nicotine eliquids, dried herbs, and hash oil.
 
I wanted to know what tanks I should buy for my current needs and even if I only need original tank and the herbal tank, should I still buy the Glass tank and the essential oil tank?
 
I also want to know some examples of essential oils, concentrates, glycerins, and waxes that are used with the vaporizers (Don't know anything about them).
 
Thanks in advance