The biggest spending was on food, which included sweets, crisps, soft drinks, icecream and school meals which the child bought - accounting for on average pounds 3.20 a week. Next down were leisure goods - toys, CDs and sports goods - which cost pounds 1.60 a week. The third most popular items inducing children to part with their cash was clothing and shoes.
Other items popular with children included spending money on participating in sport, pets, make-up and fares to school. Thirty pence a week was also spent on "other items", defined as alcohol, tobacco, stamps and subscriptions.
For the first time data on children's spending habits has been collected as part of the Family Expenditure Survey, in which all spending by children was covered
The children - more than 2,000 in total - were asked to keep diaries of their daily expenditure over a two-week period and the figures were derived from this data.
Older children spent far more than younger ones, with 15-year-olds spending on average more than four times as much as seven- and eight-year-olds. They also spent their money differently, with clothes becoming a higher priority for fashion-conscious teenagers while seven- to 12-year-olds preferred to buy toys or spend their cash on admission charges.
While boys and girls spent the same money overall, they spent it differently. Boys spent most of their money on food, leisure goods and leisure services. While girls spent almost the same amount on on food, they spent twice as much per week on clothing and footwear.
Girls also spent four times as much on personal goods and services - including toiletries, make-up and jewellery - averaging around 80p per week. Boys in comparison would only part with 20p.
Some items were bought more often than others - while more than nine out of 10 children bought food, but only 13 per cent bought clothes and footwear.
So those who bought such items were spending on average pounds 8.70 a week. Similarly, children who bought household goods spent on average pounds 1.40 a week.
Alison Whitmarsh, a statistician, said: "The actual amount of money passing through children's hands was very interesting. I'm sure I never spent pounds 8.40 a week when I was a child, but then we're not aware of any comparable surveys, so it is hard to say".
How they spend it
Food/soft drinks 3.20 3.10
Leisure goods 2.10 1.10
Clothing 0.70 1.50
Leisure services 0.90 0.70
Household goods 0.50 0.60
Personal goods 0.20 0.80
Transport 0.40 0.40
Other 0.30 0.30
TOTAL 8.40 8.50