What margin should I have on an item to consider going on Amazon?

I’ve been running my online ( shopify) shop for years, and have dabbled with Amazon. The thing is, every time I used to get an order through Amazon, I’m always astounded by the fees and shipping cost. Thinking about giving it another run again, but it makes more sense if I increase the product cost to more then what I charge on my site and give free shipping. What margins do are healthy / make sense to have at a minimum to make it worth it?