Hi Stuart, I am now into jets more than prop jobs, (and I'm not made of money!!) I started off by getting a good basic training model, and one that most people start with is a Boomerang Intro, It's a nice wooden airframe that you can pick up cheaply, they normally go for anything up to £350. (I got mine off Tony Hooper ready to fly as I part exchanged another model plus a couple of hundred quid)
the great thing about the Intro is, if you don't like the colour or it's a bit tatty, you can recover it as I have done in a scheme you fancy. (you have probably seen my avatar on RCMF)
Of course the biggest outlay is for a turbine, and as Chris said, you can get an early P60/70/80 or Wren 54 for anything around £700-£850 as long as you go and see it running when you buy it, and take someone like Steve Mitchell with you to make sure it's okay, your rocking. the only problem with the early JC's was their pick-up from idle was slower but as long as you don't go below a 1/4 throttle, it will pick up okay.
Also the cheapest option is to get a Boomer with fixed U/C or the basic piano wire retracts, as the fancy ones are expensive.
You can use standard servos on the model, but use something like an 8411 on the elevator, trouble is, once you get the bug ...............
Good luck Stuey, HTH.
Vince.