OP, eBay will let you LIST for free, but that's not the same as being required to pay a fee if the item sells.

You were clearly not told that you'd have $0 FVF. eBay doesn't do that; it's a business. Did you truly not realise that you'd have to pay a fee when the item sold?

❝Fees for auction-style listings

• It's generally free to list items. (Some limits and exclusions apply)
• You'll be charged a final value fee after the sale
• There are also fees for optional listing features and supplemental services

For full details of eBay fees, see:

• Selling fees without an eBay Store❞

You should read the following two Help pages which contain this relevant information:

https://www.ebay.com.au/help/selling/listings/selling-auctions?id=4110

https://www.ebay.com.au/help/selling/fees-credits-invoices/selling-fees-without-ebay-store?id=4822

And furthermore, as was explained on your other thread, listing with a Buy It Now price is not the same as listing with a reserve price. eBay Australia doesn't allow reserve prices, actually. The BIN price is a price that allows an impatient buyer (who can't wait until the item ends) to buy on the spot before waiting for the end of the auction, at the price that you've specified as the BIN price. It isn't a reserve price, and it disappears the instant that someone places a bid on the item.

This is all clearly explained in the relevant eBay Help pages. Did you not read through those pages before listing?

❝You can add a Buy It Now price to an auction listing, and it will be shown until the first bid is placed. The Buy It Now price has to be at least 30% higher than the auction starting price❞

READ:

https://www.ebay.com.au/help/selling/listings/selling-auctions?id=4110 (This one you'll already have read - or should have - as I linked to it above), and

https://www.ebay.com.au/help/selling/listings/selling-buy-now?id=4109

That's not even going in to the whole matter of Managed Payments. I don't know whether you've registered for Managed Payments, so in the interests of being sure you're aware of what's involved, I will assume you have not registered yet.

Selling on eBay is a very different animal to how it was five or six years ago. Are you certain you have registered as a new seller? You'll be seen by eBay as a new seller, as you have not sold regularly during the last six months, so your funds will (even in the best scenario) be held for at least 21 days - and you won't get your funds AT ALL unless you are verified for Managed Payments. That requires two distinct steps: one to verify your ID (by showing eBay your driver licence or passport) and secondly to verify your bank account - either by logging in directly with your bank credentials through a portal on eBay, or by using the microdeposit method. It's explained in the link below:

https://www.ebay.com.au/help/selling/getting-paid/registering-seller?id=4792

If you choose not to read the other Help pages about selling on eBay, you will lack vital information about how to manage being a seller in quite a challenging environment. I'd urge you to read those pages.