I won't post a full breakdown because others have done much the same already.
However, three main areas where I saved money but many people fritter it away:
Groundschool and Theory Exams: Distance learning. Probably about a quarter the price of the equivalent residential classroom course. Anyone with a bit of self-motivation should be able to get themselves through the groundschool without being spoon fed by an instructor.
Hours building: Bought a share in a vintage light aircraft in the UK. £30 per hour to fly (inclusive of fuel and landings), instead of amy £120/hr for a dull C152. I can always sell the share and get my capital back but I'm choosing to keep it because this little aeroplane is good, old-fashioned, cheap fun.
Accommodation: Most people seem to pull out their bank loans and pay through the nose for hotels etc then moan about the costs. If you do a bit of homework you can generally find somewhere quite reasonable to stay for £10-15 per night even near big UK airports. Get off your ar$e go for a drive around nearby villages and look in newsagents windows for rooms and flats to let.