I have a very nice, like new Swan Concertina that I am willing to part with now that I've entered my second year of concertina playing and have acquired an instrument a few levels higher.
The Swan needs no selling from me - it's a great "advanced learner's" instrument that looks, sounds, and feels really good. I'd say it even smells good - the leather bellows are very nice.
Currently selling for 1100 new, from Ireland. I have had it for just about one year, during the pandemic, and never took it out of the house. It has always been kept in its case when not played. We are a smoke-free home, and our one cat is not allowed into my music room where I practice and keep the instrument. I would be happy with 800 for it, and I would include shipping and insurance for the US. If going overseas, we could discuss how much that might be.