Hi BadHabit, and welcome back!
You've gotten a bunch of really good advice here so far, most of it on tanks/clearos it seems. So I'll give you my recommendation for a power unit. Something light, portable, easy to use, but with several really great features that are usually only found on mods.
SLB eGo-V v3 Mega
$36.99. Most places I've seen it have it for about the same price. I bought mine from GotVapes, but Vivid Smoke has a prettier site (in my opinion) for checking out the product.
Manufacturer: SLB (SAILEBAO).
Product Page:
SLB eGo-V V3 Mega.
I've read that SLB makes very good quality products, and now that I have one, I can attest to the same. I was impressed with my Halo ("eGo-like") Triton's build quality, but my SLB is noticeably better.
Yes, it's almost the same price as a mod. But for me, the
light weight and (slightly fatter than usual)
eGo form factor is great for portability,
passthrough is always a nice feature that most mods and eGo devices don't have,
3.0-6.0v rather than the more common 3.3-4.8v, 3.0-15.0w with
0.1w increments instead of the more common 0.5w increments,
14s cutoff rather than the more common 10s one and having an onboard
ohm meter is always nice. Those are the things which made this $37 eGo device well worth the cost for me.
------------ FEATURES
1300 mAh battery
eGo and 510 threaded
Variable voltage (VV) 3.0v - 6.0v in 0.1v increments (most VV eGo's are 3.3v - 4.8v)
Variable wattage (VW) 3.0w - 15.0w in 0.1w increments (most VW devices only have 0.5w increments)
2.5A maximum current (most devices I've seen have a 2A maximum current limit)
LCD
1 display, two buttons (+/-) for feature selection/usage
14s safety cutoff (most devices have a 10s cutoff)
Ohm meter
Passthrough charging with included USB charging cable
Hold "-" button for 5 seconds for ohm meter
Hold "+" button for 5 seconds to toggle between VV and VW
Hold both "+" and "-" buttons for 5 seconds to lock the +/- buttons (so you can't accidentally change your settings)
Hold fire button for 5 seconds to turn unit on or off
It doesn't come with a wall adapter, but practically any USB-to-AC wall adapter should work. I use the one from my Halo Triton starter kit, which works fine with it. To be sure a particular adapter is compatible, the first time you charge the unit have it next to you the whole time (generally good practice to be safe when charging new batteries or devices, anyway).
(1) Make sure the backlight on the LCD screen is on. If it's not charging, the screen's backlight will remain off.
(2) Every now and then pick up the unit and make sure it's not becoming warm. If the unit feels cool to the touch throughout the charge cycle, then all is well. (But you may already know that part.) The LCD's backlight will turn off when charging is complete. It takes 3-4 hours to deliver a full charge to the unit.
------------ PACKAGE CONTENTS
1 x SLB eGo-V V3 Mega 1300mAh Battery Unit
1 x USB Charging Cable
1 - I've seen places, including the vendor from whom I bought mine, say that the SLB eGo-V V3 Mega's display is
OLED (organic light emitting diode) rather than
LCD (liquid crystal display). The manufacturer's site and their owner's manual don't say either way. So who knows? It looks like LCD to me, though, rather than OLED.
------------
And of course, the hardware is manufactured in China, where everything else on Earth is made.
(I always wondered what China would be like to visit. When my plane lands, I would take a taxi and weave between all of the millions of hardware factories which cover China border to border, reminiscent of Star Wars' Coruscant or Asimov's Trantor. I would rent a room in a floating hotel, hovering over the myriad factory buildings, because there is no room for anything else on the ground. No wonder China needs a population of 64 billion people. They build everything in the known universe.)