I charge £1.50 per box, and I sell out at around 1000-1200 boxes per month. We sell all we can produce.
If you charge considerably less than the prevailing market price, people do not view you as a "proper" producer and will think that your product is somehow "less" than that available in the shops. Not a fair assumption, but what if someone offered you a new car, or coat or brand new laptop at less than half the retail price- honest, it is brand new- wouldn't you wonder if there was something amiss?