Disposables

A disposable, as its name suggests, is a stand-alone e-cig that you buy and can vape on straight away - no prep, no rituals. As with all e-cigs, size is important. The e-cig pictured above is bigger than a normal cigarette, about 12 cm, but has a pretty powerful battery (280 MaH) and so will deliver more puffs, and will last longer. Smaller disposables mean smaller batteries and fewer puffs, so bear that in mind when spending your money.
A note, or two, of caution - some disposables don't taste that great or give much vapour (E-lites, Nicolites, Intellicig, for example). Additionally, we have yet to find a disposable e-cig that delivers anything like the number of puffs it claims to deliver (the same can often be said of cartomisers). Nevertheless, disposables are an easy and cheap way to give vaping a try without laying out a shedload of cash. They normally retail at between £5 and £10, and, as with everything in life, one usually gets what one pays for.
Recommendation: Pay a bit more and get a decent disposable - a bad disposable can put you off e-cigs, which, given the massive advantages of vaping over smoking, would be a tragedy.