Certainly NO. Reddit will not let its end users to monetize sub-reddits and receive money from it directly. You should not place advertisements with your sub-reddit because if you are doing so, you would possibly get banned immediately. You can only leverage Reddit to spice up your own private business https://smartmoney.anythingevidence.com/worlds-first-ai-app-that-turns-your-thoughts-into-a-real-and-functional-business/