Set of tyres x3 - £300
Share of chassis price - £200 (based on a £2000 chassis over 10 races)
Share of engine(s) price - £200 (based on two £1000 engines over 10 races)
Fuel - £20(?) (control fuel - very high prices)
Entry fee for race - £80 (including Saturday practice)
Share of entry fee for series - £10 (its probably more than this)
Miscellaneous stuff - £100 (chains, sprockets, etc)
Total - £910
That figure seems a bit low for a weekend top-level karting to me. A lot of the front-runners have yearly budgets of £70,000 and more. And karting is meant to be the cheapest form of motorsport you can get
EDIT: Those prices above are just guesses and I forgot to include the share of a £100,000 motorhome