I have no idea how much profit I should be trying to make with my small boutique digital ecommerce agency. We design and develop ecommerce websites on the Magento and Shopify platform.
That depends on what you are doing and what is your target market..
The question is kinda vague but let me give you some tips..
If you are targeting a mass production / low cost strategy , your profit margin Per Sale is very low, but as mentioned it is a mass production / sale thing , so you need to make sure first you have the large market and reach your break even point, may be after a couple of thousands sale.
If you are selling a differentiated pricy product, your profit margin is really high. But you sell fewer items.
Another important factor, who is your customer ? What is the market segment your are targeting ?
Your production cost ? Shipment ? are you selling a software product for example ( so in this case the cost per unit is negligible ) ? Or selling a physical product ( so you have a cost per item.. ? )
This is a start.. You should look for a detailed analysis after providing enough info.
Reach me if you need more support and good luck !