I know of some vendors that make $1,000 a year and some that make much more than that. With no past products and a good product you might make $500, each product you add would probably grow it a bit. So if you can do three products a month you might make your $1,200 a month (Since one might not do as well as you hope). It is better to think about it per product rather than per month since, if you are only relying on your old products, you might make $50. I am not meaning to discourage you but it is a hard way to make a living. I know I couldn't do it.