If money is an issue, I would not recommend getting the $80 Janty eGo. It can be had a lot cheaper than that and, if you're willing to wait for it, about $65 from Greenhouse One and everything they sell not only comes with the six month manufacturer's warranty, but an additional six months for a total of a year.
Also, not everyone modifies their equipment. I have happily used carts with the filler with no problem. As for nicotine level, you'll settle into yours. 24 is actually pretty high, and you, like me, may find yourself comfortably settling into something in the 6-12 range, even after smoking two packs of cigarettes a day. Juices will come in such a variety of blends that it will take some time before you find the one that is right for you. It's hard to pinpoint a "best" juice provider; ask 5 people and you'll get 5 different answers. Find one who has a good sale and try them. Stick to small bottles at first, especially if money is tight. It may not be the best price per mL, but if you don't like it, it will be less painful watching a $4 bottle gather dust than a $20 one.
I also agree with LowThudd. If you spend a lot of time near a computer, a pass-through, some cartomizers, and a bottle of juice could keep you going for a long while for under $25.