Of the chronic conditions a cat can get, diabetes is one of the less expensive to manage. A vial of insulin costs between $30 and $60 and can last up to two months, depending on the dose. You can get 100 insulin syringes at Walmart for about $15. The ketodiastix are about $20 for 100 over the Internet, and last 6 weeks if you test twice a day. Please reconsider before rehoming your cat. There is a website, www.felinediabetes.com, which may be able to give you more advice. And of course, work closely with your vet.