There comes a point where you can see the difference between someone who actually needs help and the person who is too lazy to do it for themselves and wants you to do all the work. Those type of customers are not the ones you want and I don't see anything wrong with a simple note saying, "I'm sorry but I don't think our services is proving helpful to you, why don't we terminate the relationship?"
What is your time worth to you? If you think spending ten hours a month with a client who's paying you $10 a month is a good investment, by all mean continue to hold his hand and do his work for him. Sad though that you get stuck doing the work for $1 per hour while he's collecting from his clients.