Yeah, the cage can be pricey...like 150-300 dollars depending on what you get. Besides your vaccinations and ADV testing, ferret maintenence isn't too bad. For my three ferrets, I just bought a huuuge 30 lb bag of Yesterday's News litter...so that will last me 3-6 months(maybe more). It was only like 15-20 bucks. Besides that, I buy food once a month or two(ZuPreem + Eukanuba Adult)...and that's really about it. Treats are maybe another 5-10 bucks a month -- so I guess overall I'd say I spend on average 25 bucks a month on the ferret. The initial costs can get you, though. Good luck =].