Most of my gear I got off ebay, below are just examples: have a search to see if you can get them cheaper. I hope no-onw told you its gonna be cheap!
Sankey (Fosters keg coupler):
http://www.ebay.co.uk/itm/FOSTERS-KEG-T ... _500wt_938
Guiness keg coupler (you can see how the keg connection differs)
http://www.ebay.co.uk/itm/GUINNESS-A-TY ... _500wt_938
3/8" beer line (you can if you want use this fo your gas line but for gas it should really be a grey tubing):
http://www.ebay.co.uk/itm/Beer-Pipe-3-8 ... 044wt_1142
3/8" Gas line:
http://www.ebay.co.uk/itm/3-8-Beer-gas- ... _507wt_922
Mixed gas regulator (this is the mixed as version of what I have, with no guages at a preset psi):
http://www.ebay.co.uk/itm/Mixed-gas-reg ... 500wt_1169
CO2 regulator (with a guage)
http://www.ebay.co.uk/itm/CO2-regulator ... 500wt_1169
A cleaning bottle with matching keg head also is handy:
http://www.ebay.co.uk/itm/BEER-LINE-CLE ... 1392wt_922
John Guest fittings (just search ebay for john guest thenfind what you need, you'll need to work out how many of each you need)
This is the 3/8" to 3/8":
http://www.ebay.co.uk/itm/3-8-x-3-8-Str ... 500wt_1158
This is the 1/2" thread to 3/8" push fit:
http://www.ebay.co.uk/itm/3-8-1-2-bsp-J ... _500wt_938
Have you got your gases? They're a little tricky to get hold off as there is lots of red tape to get through.
If you can find a local supplier then great. But if not, again I found a guy on ebay who was selling his CO2 as part of a job lot, luckily he also had the deposit receipt for the bottle which means they won't have any problems when it comes to refilling it.
Like I said, all of the above are just examples, if you buy all new stuff it's gonna be expensive, but have good search for used gear.
Like you I wanted a smooth bitter on a pump but when I realised it meant buying 2 gas bottles, 2 regulators, 2 keg couplers, etc. etc I thought against it and got a traditional hand pump through which I pul my home brews (best decision i made, taste great through the hand pump and cheap and simple.