TBH, Wonga is pretty reasonable, if you borrow 100 and pay back next week, you will only pay about 10 pounds interest. They have 2000% APR because APR is rated interest for the whole year. You say few weeks - try the quote thing, it tells you how much you will pay back which won't be a lot as it's very short term.
BTW, I don't work for Wonga.
i agree with this
i have used wonga before in the past, and they have 'promo codes' which waiver £5.50 of the charges too.
so to borrow £100 over say 7 days, you often end up paying back no more than £110 as DavidB said
all the numbers on the ads look shifty, but they check out. i can vouch for them.
again, i don't work for wonga lol