Right, forget a marker for a minute, buy some goggles - Completely ignore your marker until you've decided what goggles to get otherwise you'll end up chopping off 20-30 to put it towards a hopper or marker and this is not a good decision.
So Goggles first, my suggestion being proto pro axis (£55 or £30 second hand but i wouldn't suggest goggles second-hand (personal preference))
Then you could get down to a walkon and ask around, try stuff out. Most people will be happy for you to have a look and a little shoot.
Marker i'd suggest an slg as it is a great entry level electro-pneumatic marker which, combined with anyone that can move their arms and legs, will definitely outperform mechanical markers. (£180 for basic, £210 for UL or £100 second-hand (much cheaper if you don't mind something that someone else has 'done things to'

)
You'll need a hopper to shoot (unless you want to load one ball at a time

) you'll probably be okay with a reloader 2 (£35 new £20 second hand) if that's all you can afford - that's what im using on my slg and it keeps up fine.
Pack (NXE packs are nice if you can afford them - very hard wearing. If not, skull packs are quite good value for money) £25 new i believe? £10-£15 second-hand.
HPA bottles, you could buy a discount one in various places for £40 + but some walkon sites allow you to rent bottles.
As for clothing, if money is no object then go out grab a set (proto 09 stuff is good value for money) or buy a second-hand jersey and put some thick trousers on (like i did)
Yeah, i've probably missed something but here's my suggestion as for gear.
If you're on a budget:
Proto pro axis goggles (£55 new)
SLG Basic/UL (£100/£120 second-hand)
Reloader 2 / something similar (£20 second-hand)
Skull Pack (£25 New)
HPA Bottle (See if your local walkon site allows you to rent, if not, go cheapest you can get (new i'd suggest though due to air being dangerous if mistreated and you don't know what the last owner has done to it))
Total: £210 + bottle (if required)
If you have a little more money:
Proto Pro Axis goggles (£55 New)
Proto Fan for goggles (£25 new)
SLG UL (£210 New - you'll have a warranty new)
Halo B (£40 Second-hand)
NXE Elevation pack (£35 new)
HPA Bottle (i'd still go £45)
Total: £410
So yeah, if you're on a budget, go for the top suggestion and build up and upgrade as and when you can. Remember, If you can't see you can't play (spend money on goggles) and if you can't afford to play it's pointless buying gear.
Sorry for such a long post, i hope this helps!