Welcome TattoodMommy!
Lots of good folk and information here.
The Mega PCC is great. I actually have one in each color, lol. It holds two batteries (will charge one at a time) and three carto's, or 1 battery and more carto's (without sleeves) in the 2nd battery trough. I would get the Pro Kit, comes with 2 batteries, some carts and the PCC, and add the 1.5A wall adapter and USB charger in addition to the kit. That will still be a couple of dollars cheaper than totally ala carte and give you three ways total to charge your batteries. I'm of the mind that an extra battery cannot hurt, either. The Volts are KR808 threading, but if you have 510 stuff, there is an adapter available from SI that will fix that little issue.
The new big battery, the X2 comes in three sizes, and will use either the carto's or the clearomizer without problem. A couple of the new X2's have had issues with the light when charging, but to my knowledge, those who had problems had replacements sent right out. It comes with its own USB cable that I plug into the 1.5A wall adapter, though you can plug it into the computer to charge. The charge lasts me between 2 and 3 days, depending on my vaping at the time. The regular 78mm batteries last me 3 or 4 hours, usually. If I marathon vape, maybe not so long. I have 65mm batteries too, and a mixture of all the batteries as far as sealed auto batteries or manual switches.
I like the clearomizer, but I like my blanks too, to fill with a whim when I want something different. Carto's also come in an extra long size. I like the regular length well enough. Love all my batteries, so I'm not really using any one battery more than another. And I have so many colors to choose from, hehe.
I like SI's pre-filled carto's better than just about any other brand I have tried. I'm glad I started with sampler packs. I eventually went back and reevaluated flavors and changed up my favorites a bit after my taste buds came back to life.
Imagine and C00kI3M0NST3R are our resident Smokeless Image reps, and they are pretty great to work and have fun with.
If you aren't sure, don't invest big, but get something you would like well enough to get by on until the next time when you feel you can order accessories or extras. (Two batteries minimum, though - one to vape while the other charges.)
All Volt batteries come fully charged and you don't have to charge them before you start enjoying them.