Hi Jay, really can't hurt to try giving up the cigarettes and E-cigs are a great place to start.
Those cigarette shaped E-cigs are a waste of time imo. I looked for the starter kit I had when I first started but couldn't find it as I guess my local E-cig shop just make them up.
Firstly I'd say it really is a good idea to get one with an adjustable voltage setting as different E-liquids will taste "better" at different voltages/watts due to the varying amounts of PG/VG in them between manufacturers/flavours.
Also it's a good idea to have an adjustable airflow on your clearomiser tank (the part that holds the E-liquid) as this will allow you to adjust to how you like the draw to be and whether you prefer a more airy or tighter draw (it will also effect the flavour slightly too I believe).
The only reason I recommend the above is because I bought a starter kit and within a few months started to spend money on better bits as I learnt what worked for me in order to enjoy the vaping more.
For starters though I have found you what I think is a reasonable starter kit. It's a kit containing a Vision Spinner 2 E-cig 1650mAh battery with an Kangertech Evod 2, charger & coils all for £26.99 (maybe postage on top).
Link: http://segonote.com/e-cigarette-kits/106-vision-spinner-ii-with-kangertech-evod-2-starter-kit.html
The only thing though is that the clearomiser in that kit doesn't have an adjustable airflow but if you feel you need one of those you can always get one afterwards for around £9 & upwards.
Really though the best thing to do is find a local E-cig shop, ...not a garage that sells E-cigs but a proper E-cig dedicated shop. If you do an internet search for E-cig shops in your local area I'd bet money there is one local to you.
That way you'll be able to try before you buy as most shops offer that service. Also you'll be able to see what sort of E-liquid best suits you and with you smoking 15 cigarettes a day the E-cig shop will be able to best advise what level nicotine content E-liquid you'll be best off starting on to replicate your normal daily nicotine intake from the cigarettes.
Fyi ~ I stayed away from tobacco flavoured E-liquids as I found it helped distance myself from the cigarettes, plus the fruity flavour E-liquids taste fantastic.
Hope that helps some and let us know if you need anymore help as there are plenty of other E-cig smokers on here (HaydnH/Andy etc) with experience to help/guide you.