Liam,
Hamish is spot on.
I'll bet you don't use half the materials either.
Obviously there is a basic tool list which you'll need but for materials all you have to do is think of the flies you require to tie.
As discussed before if you have a CDC & Elk, Klink, F-Fly, paradun, Copper coated tungsten PTN and a couple of spiders then you'll cover a fair amount of your River Don Broonie AND Sea-Trout fishing over the whole season. Other patterns can still be purchased until you generate the materials to cover the spectrum of eventualities.
Looking at these flies most require between 2 and 4 different (cheap) materials - The Klink is by far the most tricky fly for a novice and I use TMC Aerowing for the post which is expensive (£7 odds for a card) and again a nice hackle makes the fly look good but I'm sure we can sort you out with these.
Speak to Ben and see what Orvis have to offer.
I have some flies for you drop me a pm.
Iain