I paid 30 bucks for my battery. But you can get them for plenty cheaper, check out madvapes or mtbakervapor
And cartomizers/clearomizers/tanks are what the liquid go into.
Typically rebuildable one is anywhere from 6-15 bucks.
And the things you replace are either wicks or coils. And they are less than 5 bucks. Or sometimes you can buy wicks in packs of 5.
Basically... Expect about 60-80 bucks for a start up cost. And every month after that, depending on your smoking amount, anywhere from 10-30 bucks.
The higher end being if you need liquid