You don't have to spend $300.
Watch the newbie videos in the New members stickies and follow the thread with Library in its title to the multipart Wonderful World of Vaping (but ignore the superminis - they satisfy few for more than 3 weeks).
Here are the two most recommended starting models compared:
http://www.e-cigarette-forum.com/fo...st-electronic-cigarette-first-time-vaper.html
Note - the 510 is slimmer but its standard battery life is about 1.5-3 hours depending on how much you vape, less with continuous vaping - but it's a good model and if you get one I recommend Joye brand, the original manufacturer. For the KR808D-1 you can get a plain white or steel from a multi-brand vendor or check out Vapor4Life.com and Bloogplanet.com (for more color choices etc). It is a bit thicker and it's standard batteries last 3-5 hours, less of you vape constantly.
Most people here recommend MANUAL batteries, not auto. Less work (no extra drags to warm up the atty or carto), more consistent drags, more sealed against juice leaks from cart or carto, won't turn on accidentally from wind or vibration.
One good hardware vendor for basic models with cheap shipping
Electronic Cigarette Supplies & Electronic Cigarette Refills for Name-Brand Electronic Cigarettes! E-Cigs from LiteCigUSA
If you are a heavy smoker, hard dragger or need long battery life of 6-8 hours, then maybe skip the cigarette-shape ecigs and go right to something like Ego or Ego-T. Fat battery models like these have enough charge and strong enough innards to allow the use of hotter harder hitting low resistance attys and cartos that draw more power.
Prefilled carts suck
Prefilled cartos - some are pretty good
You will be refilling either with ejuice. A carto can be used about 5-7 days before performance will be too weak. SOmetimes they can be revived with washing, sometimes they die, sometimes you run it too dry and singe the stuffing and that ruins it. They are considered disposable. A cart can last a long time, you can replace the stuffing, but they need to be topped off with juice much more often and you have to take care of the separate atomizers (I swap attys every weekend and clean the used one). Attys can also die but typically last at least 5x the life of a carto.
Juices - I like Backwoods Brew and FreedomSmokeUSA for most of my juices. Other people have other faves