I want yo know how much profit margin is considered a good margin ?

In online Arbitrage and wholesale 10-15% profit margin is enough as you will be competing for buy box in wholesale and there will be no additional charges

I would say a minimum of 30 to 40 % is a good profit margin for online arbitrage products.

For online arbitrage products, I would suggest a minimum profit margin of 15 to 20% is ideal, and for wholesale products, I would say 20 to 30%.

If you are getting 20–25% profit through online arbitrage and wholesale, then that is a good profit margin. You can go with these products. Because Amazon fees are really high these days, maybe when you have estimated the profit margin, it would be 25%, and at the end, after deduction of fees, you get 10 to 15%. So, high-profit margin products should be selected so you can get at least 15 to 20% profit margin.