I dare not calculate the total I've spent on car cleaning stuff but I know it will probably be within the £150-£200 region haha. My mates got me more interested in detailing and so I used their guidance. I would help them to wash my own car and that way I saw different products at work.
My own stuff:
Optional: Snow foam and lance - Just started using the Valet Pro snow foam and does foam up well.
Meguiars lambswool wash mitt - definitely get one of these
Meguiars bucket with grit guard - Get this, the grit guard fits very well and the bucket is quite sturdy for a plastic item!
Shampoo - This is up to you, there are so many out there. I use Meguiars NXT Wash at the moment, has a nice smell and provides good lubricity. Prior to this, I used Gold class wash which was ok.
All-purpose cleaner - Bilthamber Surfex HD - Does a decent job on the wheels and around the badges/grilles when used in conjunction with a ValetPro wheel brush.
Clay Bar - I use the BiltHamber claybars as they only require water as a lubricant. I've got both the SOFT and REGULAR versions of the claybar. The SOFT version is very pliable and easy to work/roll out (fine for a new car). The REGULAR is for heavier contamination and much harder to work/roll out. If you're new to detailing, claying will be one of the best parts of washing the car, your paint will become irresistibly smooth prior to polish/wax.
Polish - I started with Autoglym super polish, a reasonably-priced product that contains resins to fill in tiny swirls and does an ok job to make your paint look glossier. It's not a proper cutting polish that will remove bigger swirls. I've bought some Poorboys SSR2 recently and this adds a little bit more cut, but don't expect miracles. If swirls are too deep/large, machine polishing will be required.
Wax - Collinite 476 - This is a very good wax that I can recommend. It's cheap and lasts ages. it's easy to apply and buff off too. One tin lasts ages, still on the first tin and I've waxed about 4 cars (each car got a few coats too).
Drying towel - I've got the Cleanyourcar waffle weave drying towel. This does a very good job, bought two of these!
Got loads more little items here and there but these are the essentials. There are so many little accessories that add to the costs without you realising initially! Wheel brushes, loads of microfibre cloths, spray bottles, applicators etc.
Other products I can recommend:
Autoglym glass polish - Makes side mirrors and glass look new - good for removing water spots (you're going to need it if you are in a hard water area).
IronX - excellent stuff that smells terrible - helps remove iron contamination. New cars won't have a lot, but you tend to find more around the wheels.
Hope this helps, let us know if you want more advice!