Is £100 pounds enough to set up a small-ish, low maintenance but half decent coldwater aquarium?
Most pet shops do starter kits with tank, gravel & filter and you should be able to get a decent set up for that. You will also need some water treatment solution. You should take the kit home & set it up with treated water & leave it for a week before putting your fish in. Also when you buy the fish they should be active with clear eyes & scales. You will get them in a bag of water & you should put this unopened in the tank & leave it to float for at least half an hour so when you open it the temperatures will be the same. Don’t get carp as they grow too big.