Great advice from Alice & others above.
I'd definitely agree with getting two ferrets because they need company & they will play together. If you don't get a well-socialised rescue ferret I would recommend getting them young. Ours were four months when we got them & they can be a bit nippy. If you get them as young kits you can train them not to bite, & this is important as ferret bites hurt and leave scars
My sons have two ferrets, neutered males from the same litter. We've had them about four or five years now & my boys were about 14 or 15 when we got them. I wouldn't recommend them for young children at all because of the biting risk.
Our ferrets live outdoors in a large custom built hutch, and they also have a separate outdoor run. Ferrets need large hutches with lots of space to play. They are very lively when awake, then they'll curl up together & sleep for hours. They can escape from anywhere, so their runs need to be very secure. Ours have got out a couple of times, but we know where they like to go so have always managed to track them down so far. One likes to take off across the garden & hide under the shed, the other one runs about for a bit then heads back into his run when he's tired! One of them will actually come to his name when called.
Ferrets are very entertaining, they are like playful kittens which never grow up. They are curious & determined little creatures, and very clever - DS1 has taught his ferret to use the cat flap
- and they love toys, especially the occasional bowl of water to splash in. DS1 walks around with them draped round his neck like little furry scarves. I occasionally allow them in the house if it's too wet for their outdoor run - we have to secure all the kitchen cupboard doors or they'll open them & disappear behind the units.
Lots of people don't like the distinctive ferret smell, but I don't mind it. I think because our boys are neutered they don't smell so strongly, but it's a warm, earthy, musky smell. I wouldn't want them in the house all the time, though.
On the subject of walking a ferret, you can't walk a ferret on a harness, it'll walk you! You have to go in the direction the ferret wants to go, and that's assuming you can get the harness on the ferret without losing a finger.
One more little tip. Ferrets need their nails clipping regularly. It used to take three of us to do it until we discovered that ferrets adore cod liver oil. One little drop on his tummy & you can do anything with a ferret as he'll be so busy licking it off he won't even notice he's having his nails clipped.
Sorry about the essay - I'm sure you can tell I'm quite fond of our ferrets 