Buying a cage is the largest expense in buying a mouse but it is also possible to build a custom cage from relatively cheap items.

As a guide, the minimum floor space of any cage for 1-2 mice should be 2 foot x 1 foot, with at least an extra square foot of floor space for each additional mouse. It is important to provide the best and largest cage for your mouse/mice that you can as this is likely to be where they will spend much of their time.