An app/website where you can swap gently used children’s clothing that your child has outgrown that can be exchanged for clothes that currently do fit. The only costs are a fixed shipping price per outfit swap regardless of brand name or size. Fixed costs for consumers and clothes are not being wasted and collecting dust.
Sure this would work for adult clothing as well, but take a drive around during garage sale season and notice the mountains of kids clothes trying to be sold for pennies. Pretty sure those people would like to get an complete outfit in exchange instead of a few pennies.
I can see where it might be more advantageous to have multi-armed swaps, Person A swaps with Person B, who is Swapping with Person X who then finishes the swap with Person A. That way sizes and taste can be accommodated.
Or, you have an outfit, you send it out into the ether and earn a 1 outfit credit. You can then use that 1 outfit credit to order the exact outfit that you want from Person A, who will then get a 1 outfit Credit to use as they see fit.