I would probably say at least 2 FC for the Bastet skin since it's an older item and pretty popular.

Some skins are a lot higher....
I had a looking-to-buy thread for an Anubis skin for about a month offering 90k and no one would sell (repurposed it eventually, of course).
The coffee Bat Halloween skin is pretty up there, too...

And some skins are still much lower, like the Valentine skin or the fire-orange Halloween skin or the lavender/blue Easter skins. I think those are still around the 5k or 7k each mark.

For a Bastet skin, I got mine from the Market, one of the items Her Ugliness was auctioning. Quick search of the activity log and.... I paid a little over 16k for it.
(Which honestly is probably on the very low end, but it gives you a ballpark).
There's been a lot of inflation just in the short time since then, so...

Yeah, people can't decide what things are worth.

Thank you all veeeeery much indeed! At least now I've got an idea of how much I can ask... not FC, because it's something near a "gift" so I'll think I'll ask her 15k ^^ I didn't use it and it's in her wishlist and I would give her for free but need a lot of FP for my personal hunt for items soooo XD

You're all very kind to have answered me in this short time, thank again :3

No problem dear.
Good luck with your FP hunt!

Thanks ^^ I've a lot of items to catch up, knuffels too... so, yes, all the luck is very welcome XD

Which reminds me, I should go list another batch of extra wild knuffel items again.

... after food. Food first.

I'm glad we could help, though!

List a batch? o.o

Well, you know. You go along leveling up your knuffels and end up with a slew of duplications, and at some point or another you list them in the Market.
A batch at a time.

Oh oh I missed the word "items" XD