I have two (pixie & dixie)
they are easy to keep in the correct cage/tank etc
yo need to be able to spend some time with them each day, handling, playing with them.
I would get two or more related mice, preferably femlaes (sisters, mother daughter etc)
as unrelated mice tend to fight a lot. Male mice spray a musk everywhere so it is them that have
made people think that mice smell,the don't.
you should clean out their woodshavings twice a week becuase mice, unlike most other rodents) don't have a specific area that they use as a toilet, they go wherever they are.
you can fed them pretty much anything that dosn't contain salt
but avoid apple pips, as the small amounts of cyanide in them will kill the mice.
Mine love watercress, lettuce, cucumber,apple, banana etc.
fresh fruit and veg should be a staple part of their diet along side the "std" rodent mix yo buy for them.
HTH