hi i just started breeding rats and i still buy rats from a local kid who breed and sells rats as pets i get all his extra at .50 cents a rat for small and i get about 40 a month from him plus from my breeding of rat i get about 40 a month and i fifty puond bag a food for the rats cost me 10.00 and last about 2 month and a big bag of bedding last a month and that cost 6.00 on sell plus the electric[sp] i would guess about 50-70 buck a year and probaly closer to 50 a year