There is an app here on Etsy called Shipsaver.
No I don't work for them.
At first I was very hesitant to sign up.
It cost$1 for $100 worth of coverage and they cover the cost of the shipping, which the USPS does not. It is slightly more for international packages and they do insure First Class International.
I am assuming it is available for all Etsy shops, but may be wrong.
I had a claim. Filed it on a Wednesday, got paid on a Friday, shipped the customer a new item, and the insurance paid for the shipping too.
I look at it this was, and you can disagree, because what I do many not fit for your business.
If I drive to the store to buy something, I have to pay the gas, car insurance, etc to get there.
If I want to exchange it, same thing, my cost.
If i have a wreck, it get rained on on the way to the car- like cat litter- or something happens to the items on the way home, my fault, I eat the cost as the customer.
S I think insurance is for the buyer and the seller. It protects us both, at a very minimal cost.
It sure saves both grief because of an accident that is no fault of either.
If you have an off Etsy site, the same company has a web site called Insurepost.