Oh, and be careful of "Equivalent to X packs of cigarette" claims. These are, at best, usually exaggerated, and at worst, flat out lies. It's really kind of impossible to look at it that way...
Various equipment setups burn juice at different rates. Further, you can't really look at it the same way. You can't say, "I smoked a pack a day, so that's 20 smokes at 5 minutes each, so I need X amount of juice." You will likely not vape the same amount of time and in the same way you smoked. Your body metabolizes this in a different way, so it's not really a comparison situation. It's difficult not to think of it that way, but it really doesn't work out like that.
In my case, I spent a good bit of money up front looking for the perfect equipment that didn't leak, offered good flavor and good vapor production. Once I found my hardware, I was all set. I mix my own juices for pennies/mL, and it's a very low cost endeavor. It may cost a bit to find a setup that you like and you can deal with...
Find something you can use to stop smoking (if that's your goal), and then worry about saving money... In the long run, you'll save bundles, and you'll be so much healthier. I hate to see people give up and go back to analogs because they don't find the right equipment for themselves... I did it myself three years ago. Very happy/fortunate to have found this group that helped me get back on board and find exactly what I needed.