My understanding is that when working this out, until you have some historic data (as mentioned above) you pretty much have to make some assumptions. You need to either ask yourself how many items you can sell per month, or how much in monetary terms can I move each month... bearing in mind you’ll have slow months to start with, etc.

You then need to work out your costs... add then apportion this across your goods... for example if you have costs of 10,000 per month, and you believe you can sell 5,000 items then your apportioned overhead would be 10,000 / 5,000 or $2,00 add to this the cost of the product and you have your break-even price... and you’ve already set your break even sale figures of 5,000 units.

The above is rather simplified... when I used to regularly work such things out; I used to apportion 33% for unexpected quiet periods, damage goods, etc... the more you work out your costs, potential costs, etc... the better you can manage them within your cost structure... and don’t forget that once you have your break even price you then need to add in your profit.

Hope this helps.