Pet Mouse Care
I'm in the US so my info will be based on that.
Life Span
Something to keep in mind is that mice can live 1 to 3 years. They can live longer, but that's quite uncommon. The average age is from 1-2. They're not a long term pet unless you plan to have a group of does you continuously add to.
Friends
Mice are social creatures, but bucks do not get along with each other. It is important that if you are going to keep mice as pets, that you only have a group of does, or a solo buck. Does should get along with each other, but occasionally you may find certain ones to be more territorial or aggressive towards others. This should not be considered normal behavior, but is more common among pet store mice.
Cage
The easiest and safest option for a pet owner is a tank. A 10g would be suitable for a buck or a trio of does. (Bucks are aggressive towards each other after 4-12 weeks of age.) Barred cages can potentially work, but if your mice are too small they could escape. Most pet store mice fall under this category.
Bedding
I recommend wood bedding as it controls ammonia the best. Pine, aspen, and other woods are fine. No cedar, as it's carcinogenic. It doesn't need to be very thick, so 1-3 inches would work fine.
Cleaning will depend on how many mice you have, in what size of enclosure. Generally once a week to once every 2 weeks will work.
If you have paper bedding that they should be cleaned every 3-4 days. Paper does not neutralize ammonia, so you need to clean often to avoid build up. Too much ammonia can damage their lungs and cause respiratory infections.
Enrichment
Hides: They need a hide they can retreat to, though several would be ideal, especially if the cage is in an area with lots of noise and movement. Plastic hides and small boxes work well.
Nesting Material: Additional nesting material like shredded paper would be great. They'll shove this into a hide they like or build a nest in the corner.
Destroyable Material: Other chewable items like small cardboard boxes, egg cartons, or toilet paper rolls are great. These can easily be thrown out during cage cleaning if they get dirty.
Wheels: They generally quite enjoy wheels, and I personally like the saucer type best. Some mice may not use them though. It is more common for calmer low energy mice to focus on nesting more than running.
A key thing with mice is that less space is better than too much. Mice are pretty low on the food chain and too much open space can stress them. A cluttered cage is ideal. Humans like our open spaces, but not mice! Be wary of people who say, "A male mouse needs a minimum of 20-40g". They're likely ignoring the mouse's needs and projecting their own.
Diet
Food is simple. They're granivores, so grain based blocks are perfect. Mazuri is a good brand that sells small bags in most pet stores in the US. Katy is, so-so. Just try to avoid excess dyes primarily. Bird seed, millet, and sunflower seeds are great treats, but should be used sparingly. A small pinch daily or every other day would be fine. Any foods that have such treats already mixed in can cause issues if they only pick out the treats, leaving the rest.
They can technically eat fresh plants and veggies, but I don't recommend it as it can give them diarrhea. Their diet should be dry if they have access to water, as domestic mice should. During transport (if more than 30 minutes) veggies like cucumbers can be given for hydration along with food blocks.
