Dance costume selling app

Description

A online costume selling app designed to be a one stop shop for all dance costume needs. An app like vinted/ depop/eBay that is dedicated to freestyle dance costume selling .
Currently there is not one place to go for our dance needs . Multiple Facebook groups is the main place to sell, making it hard to keep track of, many fb messages over different groups , and also finding a costume u saw before again proves hard. There is also a lot of issues with non dancers and men sending messages to buy children’s outfits - asking for photos of it on the child ect.
I want to create a safe app space designed for selling children’s costumes . Sellers have a profile - list the school they are from and can be verified by the school . Sellers can be rated also on previous sales to make them trusted sellers . Some of these costumes can be up to £1000 still second hand , so want to minimise risk from buying over fb and make it easy for sellers to sell and buyers to filter and search for what they are looking for.
I would also then run paid ads using data from peoples profiles , and paid boosted posts for people to sell.