profit margins question

Hello, I have a very important question which will decide the fate of my possible business idea.



is there a minimum margin profit requirement before selling a product?



I mean, a profit margin of 50%, is it okay? So I sell a product for $100 and it cost $50 to make, is it a good business?



But after taxes it will be probably more like 20% profit or so, is it still okay to do this type of business where I make $20 on every $100?



Thank you!

Martin