I've been on Detailing World for about 5 months now, it's all great but detailing gets additive. So far i've spent about £650 on detailing items.
My one tip for you is to buy Blackhole glaze and to clay the car before polishing and then finishing off with a great wax or sealant, everyone's favourites this winter are;
Collinite 476 - used on my car too and it is great
Finishkare 1000p - great sealant and does great on alloys too.
If you get fully into detailing I strongly suggest Gtechniq items as I've used the nano coat windscreen kit and the permanent bumper restoring stuff and it's the best stuff on the market, really worth the price.
Make sure that you have the routine down to a tee -
Snow foam if possible or rinse with a watering can
-leave 5 minutes or so-
Wash using a two bucket method
-rinse-
don't bother drying if your using clay and then get some lube for the clay, I used demonshine with a 5:1 dilution, works wonders (cheap too)
once finished claying all over, just give it a nice polish and buff it off after it's cured.
and then apply the wax/sealant.
goodluck with detailing and feel free to pm me if you have any problems at all.