Just go buy a 30 dollar rat/mouse cage from Petco. We do this all the time. You can guy actual rat food or just give him crushed up crackers and like Cheerios. Make sure it has water and bedding. As long as it has fur and it's eyes are open, it'll be fine. It will grow but not a major amount in a week.

Sent from my XT1254 using Tapatalk