Would you prefer to have a cage or carrier?Carriers would be much cheaper,but a cage that isn't quite big enough for permanent living but still a good size for a pair temporarily might be a good investment in case of travel and such.
Alaska Hamster Cage | Free P&P on orders £29+ at zooplus! For travel purposes the Alaska would be wonderful,since while it is quite short for permanent living it would be great to use as a travel cage for rats or as a cage for elderly rats that can't climb as good.
Pico Transport Box: Free P&P on orders £29+ at zooplus! Or just a cheap carrier like this!