There is something strange going on.
Last night a link to the ebay advert was posted here:
https://www.head-fi.org/threads/earbuds-round-up.441400/page-2673#post-14780369
When I clicked on it the price was shown as $10. I checked the advert via my previous order and that still showed as $8. Now last night's advert has been withdrawn and the original is showing as sold out.
I think the advert will be re-listed at $10. I'm only guessing but I presume the seller has seen how popular they are on this thread and has upped the price. We shall see.