The school, which has been given the cash by the Government's New Deal for Communities inner-city regeneration scheme, is one of several offering the payments as it struggles to improve results. The proportion of pupils achieving five or more GCSEs at C or better has climbed from 17 per cent in 2000 to 27 per cent last year.
Sophie Annesley, who oversees the initiative, said: "Year 10 students receive pound;10 for every predicted grade achieved, pound;5 for any grade above the predicted grade and pound;150 for getting five A* to C GCSEs.
"One student got the highest amount, pound;360, last year for achieving her predicted grades and above. The general consensus is that the money has gone to useful things such as a motorbike or materials for college courses, but I'm sure a lot of them probably spent it on trainers."
Ms Annesley said the cash had particularly helped children from ethnic minorities. The five A* to C rate for these pupils improved from 1 per cent in 2000 to 20 per cent last year, she said.
City Academy received pound;328,000 for the three-year initiative, which also pays for Easter revision classes, tutorials and after-school clubs and offers pound;500 to every student who goes on to university.
Peter Davies, education co-ordinator of Community at Heart, a partnership overseeing the scheme in Bristol, said: "When the money runs out in 2007 it will not matter as the scheme has created a culture of achievement within the school."
More schools are using payments as they face pressure to improve league-table positions. Schools in Brighton, Birmingham and Plymouth operate similar schemes.