We have three, feret nation cage and a large area/enclosure for them to roam. The smell for most is manageable with baths once a month with baby shampoo and tea tree oil shampoo (specific for ferrets). They are preverbial shit boxes. They live to eat, sleep, shit and repeat. Daily cleaning of the cage is a must to keep the smell down.
When they are awake they are peppy and fun. They are emotional creatures and will get depressed if not attended too. So attention is needed to keep them from getting bored. Toys, new experiences
(Like going out side) are treats for them. Just make sure you get a harness so you dont lose them. Ours love digging in soft dirt and snow.
Food wise they cannot process grains, so grain free food is a must. (Most grain free cat food is good for ferrets too). They will need a vitamin supplement to help their diet called ferovite. About half a teaspoon a week is all its needed. And they love peanutbutter. Havent met one yet that didnt like it. We use it as a treat for training or a reward. They are very sensitive to sugar (like grain they cant break it down) so as much as it seems they like it dont give them licks of candy, cookies, etc. Ferrets are prone for developing insulinoma (kinda like diebeties) if given too much sugar it can cause it to develope faster. Some fruit every now and again is ok but only once in a blue moon. I usually give them bananas or pumpkin.
They can live for upwards of 8-10 years so they are a longer commitment. If you're not sure you want one for that long, I would suggest adoptiong one from a rescue page as upposed to buying one at the pet store.