@LeoSammallahti sounds like good incentive to produce higher quality (or at least more popular) articles.
At 1 cent there would really no reason to have free content other than for marketing purposes to attract new users (members). 5 to 10 cents would also not be unreasonable. How many quality articles can one expect to consume for $1 any way.
A big hurdle you have at a $1/month is the processing fees as a % greatly reduce revenue available. Batching a couple months help a little.