If you are selling stuff, anywhere, the general guideline to set sale price is

1/3 net product costs including losses

1/3 operational expenditure such as overheads (rent/fees), wages, utilities, depreciation on equipment, stationery etc

1/3 profit

So, if you can't make your product fit into that criteria and sell at a price that the market will bear, then it is not a viable commodity to sell on that particular platform.

The answer - find a different platform or a different product