If you buy something that has atomizer and cartridges than it may need
juice added often. As a heavy smoker I recommend you look at things that can use cartomizers or
tanks - they are a slight added expense but they hold more liquid and vape more predictably than a cartridge. Cartomizers are most available for 510 and KR808D-1 threading and less available for DSE801 and DSE901, and probably just one type available for RN4081. Those are the main threadings for cartomizers.
If by heavy smoker to you mean hot drags etc then you also want to look for something that can use low resistance cartomizers or
tanks. Only batteries 450mah and above can usually use low resistance stuff. If you were not looking for a cigar look then I would recommend Joye Ego or Riva 510.
I know there are some E-cigars here. Looks pretty pricey to me. You could try the disposables.
Greenworld Cigar Type eCig
If I was you I would continue looking for something that can take standard cartomizers in a popular threading. Those $55 cartos seem awful high. I pay about $12 for 5 prefilled cartos for a normal mini ecig (120mm, standard Vapor4Life)