I've found two girls by searching on the Net they'd be the perfect flatmates in London. The first one is named Bettina she's 26 years old german female, medical student, no smoker, need a flat for 2 months and has 300-700 pounds of budget. The second is named Annesophie she's 22 years old denmark female, art student, no smoker, need a flat for two months too, and has similar budget. And Peter has two rooms to rent in Highgate, London. The minimum stay is for three months but I think they could negociate with him nd they'll be able to rent the rooms for two months.
The most expensive city is New York. Near Central Park it`s a madness rent. The cheapest is Sidney; nice views, nice flat and nice price.