Why won't my mom let me get a ferret? She's not going to buy it I am.. So why is she saying no?

She doesn't want one in the house.

They're not like a puppy or kitten, they can't be 100% litter trained (you WILL have accidents when they're out of the cage). They need at least 2 hours a day out of their cage. They get inside furniture like couches and are nearly impossible to get out of those. They live maybe 5 years, most die from some sort of cancer. They need a special diet or they get nutritional deficiencies. They can't be kept around caged birds or small rodents. They WILL find the one spot you didn't ferretproof. They tip over potted plants and garbage containers just for the fun of it, they CAN bite hard too. And they will have a smell, even when descented - they're mustelids.

The poop reeks too.

Well what reason did she give you for not letting you get one? Ferrets are a lot of work, and the smell. I had one when I was younger and he was great, but the smell and maintenance can be off-putting.