There are some things that you will absolutly need on a regular basis for you mouse. You should have a food dish. These are rather inexpensive, and sometimes free if you know where to find them. Do you save you old peanut butter jars? Try using the lid for food. It is the perfect depth to hold about two or three days worth of seed ((for one mouse)) Also, to keep the food fresh, try storing it in an oatmeal container. And mice don't necasarily need this, but some plastic tubes to lay on the floor of the cage provide them with a place to sleep, and something to stand on. They sell it in most pet stores... that I know of. Also you need a water source. You can opt to buy a water bottle if it will fit in your mouse's cage and if you have the money, or you can go the other route and just use something laying around the house as a water dish. If you use a water dish, do make sure that you keep it fresh, as a mouse can kick litter into it making a soggy mess.