What kind of capacitor do i need, high or low farad rating?

I am in need of some capacitors for a capacitor bank project i require for school, i want to build a bank with as high as possible voltage and make sure it discharges in as little time as possible, to charge the bank i will be using is from a disposable camera flash, keeping this info in mind and the fact i will have a budget of about $20 total what would you recommend, does a farad rating have any bearing on the rate of discharge?