I would suggest something like iStick Basics or Joyetech eGrip Oleds and few different flavors. Easy to use and you can use premade coilheads. Also, those two are most preferred for smokers who want to vape due to tighter draw and not that much vapor.
Also, if you aren't a vaper yourself, I do suggest keeping your money and perhaps trying to get your friends to get their own vaping equipment. Also, as far as higher powered mods and tanks go, I think you still want to see more than 2m in front of you. I can cloud up a ~30 sq.meter livingroom in few drags off of a modified Bellus on top of a iPV3 Li running at about 50-70W.
iStick Basic would be preferred to be honest. Cheap mod and tank combo, easy to use and internal battery, no need to worry about battery safety, only thing you need to worry is to provide decent amount of MicroUSB-chargers.
The eGrip Oled is a mod with a built in tank and battery, but they are more costly and leak quite easily with wrong types of liquids used.
There are cheap "stick-type" batteries and tank combos suitable for Sub-ohm vaping (huge clouds of vapor) like the Joyetech eGo One-series.