Hello Nathan,
Welcome to the forum (although I'm pretty new here myself). Also congrats on purchasing such a lovely car at such a tender age!
My last car was Candy White (Golf 122PS) and its actually pretty easy to look after apart from the fact you have to deal with those little yellow fallout marks and not expect it to look good in winter the day after you wash it! Do a search on candy white on this site and you will see lots of helpful comments and links on how to look after it including this thread
http://www.sciroccocentral.co.uk/forum/ ... 31&t=12663" onclick="window.open(this.href);return false;. AutoGlym products seem to have a reputation on forums as being a little 'old fashioned' and the hardcore guys prefer professional detailing products such as those made by Auto Finesse, Meguires, Poorboys etc. You will see Megs stuff in Halfords but you might want to check out on-line specialist supplier Polished Bliss who have a great website and post products out free of postage charges. They are also very helpful on the phone (I have no connection to them by the way - apart from being a satisfied customer!).
Wheels are a subject in their own right (and a big one!). Now you say 'obviously' it has Interlagos.... well, the Interlagos 18" alloy is not standard on the 122PS cars - its actually a £450 option - so if you have them fitted you can thank the previous owner for ticking that option box or adding them later. I only got my own Roc two weeks ago - the alloys were very clean so all I did was wash them, dry them and add two coats of AutoGlym Wheel Sealant. OK - not one of the 'pro' products but it does prevent bake dust build up if you re-apply it every few months (you van buy other similar products from alternative manufacturers of course). You will then only need car shampoo and water to clean them - no special cleaning products necessary. Be careful with the black plastic bolt caps as these can easily discolour with the use of alloy cleaning products.
If you get black spots on your alloys - which don't clean off (often they are seen in the corners where spokes join rim and NOT to be confused with tar spots) these are metal particles which have embedded themselves in the upper layer of the paint finish. You can remove them very easily by purchasing special products: 'Iron-X' or 'De-Ironiser' are the two that spring to mind. Again a quick search or look on the PB site will give you lots of info. These products can be used on your paint to remove the yellow fallout spots too - but follow manufacturers guidance carefully!
Normal tar spots on the paintwork (very visible on you CW car but less on my DB) will dissolve using a proprietry tar remover as part of the wash cycle - the general concensus seems to be Tardis as a good selection but of course all the major brands make their own products for this purpose, including AG's Intensive Tar Remover - perhaps 'old fashioned' - but it does work!.
Once again - look here or on Detailing World for how others go about washing their cars - it can get very specialist - snow foaming, clay baring etc - you just have to find a method you are comfortable with although I would strongly reccomend at least using the fabled '2-bucket' and wash-mitt method as this does reduce the possibility of paint damage significantly. Whatever you do - don't be tempted to take it to a 'hand carwash' - use of sponges will ruin your finish.
Actually giving the car a clay baring is a good idea (although if you have never used one before it does seem like a very weird concept) - however I guarantee you will be amazed at the effect it has - Meguires do a nice kit with everything you need in it for £25 - its definately worth doing and again, there are plenty of other makes available and everyone has their own choice, including 'Bilt Hamber' bars (yes another strange name!) which don't require special lubricant and can be used with water.
Waxing - in terms of choosing a price level - thats like asking how much does it cost for a new kitchen - you can pay just about anything for car wax - I have just purchased some and went for Auto Finesse's base product (they make three levels of product with alluring names such as 'Temptation') - it was £25 for a small pot but you can pay hundreds if you want... I chose it on the basis of the manufacturers reputation, the price level I was comfortable with (near the bottom, lol) and the fact I have other AF products which have worked well for me (nice packaging designs too). You may also try out their Citrus Power cleaner which is a spray on pre-wash product which I found worked well for loosening dirt on cills and wheel arches.
I think with car cleaning products its like many things in life - you get comfortable with one manufacturer for the majority of your purchases and end up sticking with them - but at the start its a good idea to try to use a few different brands and make up your own mind.....
Have fun with the car :-)