Ok, ive got the wonders of a mastercard and i need to buy a plane ticket for £541. Unfortunatly i have a limit of £500 (which they wont increase as im a blooming student). So im thinking if i funnel in £100 of my money into the card, ill have £100 worth of my money on it. Therefore allowing me to buy somthing worth £600. (£100 of my money + £500 credit limit) Is that going to work or are they going to tell me to sod off? Many thanks for those who helped.