Just drop the store bought cigalikes altogether and get yourself a halfway decent tank like a Kanger protank mini or an evod and get some juice. You're wasting your money with cigalikes. You can get a very basic evod starter kit for $15 from vape dojo (it's called the katani kit I think), and you can spend a few bucks with them for some juice. For me about 2 to 3 ml I think would "equal" (if you can even compare the two) to a pack of cigarettes, so if you're spending say $7 on 15 ml of juice you'll be getting anywhere from 5 to 7 packs equivalent, and that's the real deal, not just some words on a package.
(and if you think about my math, 2 - 3 ml of juice would never fit into one of those cigalikes so how in the world would they ever equal that?)
Well IME the average cig alike tank holds a solid .8ml - 1ml. So if its 24 mg/ml and your saying 1 cig = 1 mg of nicotine you could say its equivalent to a pack of cigarettes... Without lying... But it is far stretch from reality.
If you really want to have a decent device that is cig-alike sized and shaped I think your best bet is the eroll type of setup. The tanks are refillable holding .7 ml of juice... The atomizers with the little spike work pretty darn good, possible to rebuild (pretty much same as ego-c/t or eroll), comes with an awesome case charger... It won't really compare with a genesis style hybrid, a clearomizer, or any fancy mod though.
For the ml to pack comparison... I really feel there are too many variables at play for it to be defined outside of the individual. I used to smoke ~a pack a day on average. For the first year after switching over I averaged ~8 ml/day at around 25 mg/ml. When I would go camping/fishing/out drinking/long drives I would need ~2 packs a day. I have old backpacking trips planned with 1.5 packs/day over 14 days as a space compromise with food and clothing limitations... Now I plan around 10 ml/day and one 18650/day for such events of personal indulgence around 12mg/ml. My average daily intake has settled somewhere around 5 ml/day around 12 mg/ml.
The point being that I strongly feel the devices that push pre-filled cartridges in limited strengths / flavors / pg/vg ratios are very detrimental to ones e-cig experience. Not only will it save you a fortune but it will also also you to take control and personalize your nicotine intake.