Welcome to ECF!
I haven't learned a whole lot yet on my vaping journey, but I'll share with you some of the questions I've had to answer for myself:
* What form factor do you want?
In the beginning, I was all about the long and skinny cylinders to remind me of smoking. Even though they were heavier than a cigarette, I'd periodically hold them between my fingers as if they were cigs. Overall the 2 eGo batteries that I bought were not that great, but at the time I was very "anti-box". If you can deal with something that doesn't really look at all like cigarette -- great! You'll have more options for set-ups, and if you're serious about all of this, you can avoid spending money on stuff you'll outgrow in two weeks. But don't worry if you don't want to invest in sophisticated "mods" right now. Many folks, including myself, have quit with relatively simple eGo setups.
* How long do you need them to last?
Or, how many batteries do you want to carry with you? I started with batteries that said they'd last 6 hours and 9 hours. This seemed to be enough for a work day and well within my price range. But after a month, I realized that they were slowly, slowly losing their mojo. And while both still work, they no longer achieve anything near that length of time. AND -- there were a few days when both of them needed to be recharged at the same time! EEK! I wanna vape RIGHT NOW! was all I could think, followed by - that convenience store is open, I could pick up a pack of smokes right now! So, I solved this with buying a few devices with pass-through capabilities, meaning I could vape them while they were charging. Yes, extra purchases that I could have avoided with a more powerful battery up front. The recommendation above for a couple of rechargeable batteries and a Nitecore charger might be right solution for you. I haven't gone down that path yet, so I can't really comment more. All I know is that BACKUPS FOR YOUR BACKUPS is the way to go, especially in the early days, when you're still used to buying cigarettes.
* Are you crafty?
If so, rebuilding may be for you. It's not for me. My papier mache sucked as a kid, and my hand-eye coordination hasn't improved a lick. In fact, my eye sight is worse, so winding wire around drill bits and stuffing them with cotton isn't my thing, especially since the final result will, upon occasion, be close to my face, and I'm not confident I could avoid disasters. Me, I have atomizers that I buy coils for every other week or so. But a rebuildable atomizer might be just the ticket for you. It saves money and lets you customize your vaping experience. If you've been reading up on this stuff here, and it appeals to you -- investigate some more and skip the tanks that tie you into buying coils every week. But rest assured that even if you choose to use ready-made replacement coils you're A: Not smoking! and B: still saving money!
Hope this helps! If not, keep asking questions. Smarter folks than me are floating around here all the time!