I think those price estimates you've been given are very optimistic !
You can buy a brand new Pentax XW landed in Australia for ~ $350
https://www.kyoei-tokyo.jp/shopbrand/ct1499/
Not that they aren't good eyepieces, it's about what other options people have.
I think $200 is a more realistic expectation. I saw your adverts in the classifieds. You might get some nibbles at those prices and I hope you do, but I think your expectations need to be realistic.
Cheers
John B