How can I convince my parents to let me get a ferret or rabbit?

Tell them its better than having a child

Know anybody who has a ferret or rabbit as pets. Perhaps you could arrange to pet-sit for them (with your parents permission). You and your parents would both get an idea of what it would be like if you owned one.

Okay, I've noticed now three of your posts. 1) Don't even think about talking to your parents until you know exactly how much a rabbit/ferret will cost. ON AVERAGE a rabbit will cost less than a ferret. Usually the rabbit themselves will be around $40, the cage a minimum of $150 (they need space especially if like you said earlier, you only want to take them out for "an hour or two") Food is a minimum of $15 a week, plus Timmy hay, $25 per small bundle. (They HAVE to have Timothy hay for their digestion, they can die prematurely if they are not provided with this) Plan on spending a minimum of $50 on toys, rabbits need to have mental stimulation just like every other animal. You're looking at an upfront cost of over $250 plus a monthly maintenance of $50 a month. 2) If your parents say no, don't go out and get one anyways, that will diminish their trust in you and you will never be able to get the pet that you want. Act responsible and prove that you can handle your own pet. 3) If you can't spend the upfront cost of the rabbit/ferret (ferrets need larger cages, more toys, and they need more mental stimulation plus human interaction if you have only one.) get a goldfish. Rabbits and ferrets both need antiquate space, veterinary costs can come into play, and sometimes they do better in an outdoor encloser. If all of this scares you, you need to wait. Being a pet parent is a real responsibility, not something you should do on a whim.