If you change your mind then the return postage should be down to you but if you return because you suspect it is faulty and this turns out to be the case then it seem unfair that any postage is your responsibility.

So it would never be sensible to return even faulty items if the total postage came anywhere near to the purchase price plus sender's postage cost.

Isn't there an equivalent law to what in Britain is the Sale of Goods Act whereby the goods have got to be "fit for purpose" and if not, all costs are down to the seller.

As you describes things, they seem like a win all ways for the seller and lose all ways for the buyer