Permissible and impermissible items of trade

Selling animals for fighting

Q: For animals used in fighting such as roosters and dogs, their price depends on their fighting ability. If a rooster/dog is an excellent fighter, it would be expensive. So is it halaal to include the price of an animal's fighting ability in the overall price of the animal? Would the amount added to the price based on the fighting ability be halaal?

Purchasing a TV on interest

Q: I bought a TV with option of no cost emi of 3 months. After emi completion, Later I found out that it is not permissible and it involves interest as bank gives loan and charges interest and then I checked my statement and found out.

I usually buy items paying all amount but this happened first time that I had to take this option of no cost emi. From the day, I came to know I am feeling bad. Should I sell of my TV or keep it? If I sell I won't even get 50% of amount which I took. So I am in a dilema. What should I do in this case.