I have an 11 month old lab, can anyone tell me roughly how much it cost for castration?

Sorry it differs in different parts of the country, if you can't I would leave it at least another year before you have it done as the earlier the more chance of unwanted side effects so the later the better. Guess you must have a bitch or neighbours with one and if that is why you want him done then perhaps kennelling may be the answer until he is fully mature.