Trying to list just But it Now

Is your feedback number low? If so, you can't use BIN until it's (I think) at least 10.

No, it can't be that. my feedback is 234

You must enter a starting price for example if you want to sell a item BIN for 15.99 and do not want to sell for less than that enter your starting price as 15.99 or possibly 15.98 if the system will not allow you to enter BIN 15.99 and starting price 15.99.
I use BINs but have never done it this way but have seen other sellers who do as you are talking about.
Edit: Hi Miss S

Are you selecting Fixed Price at the very top of your create listing page? Maybe that's it?

Hi Taz

Miss S may be onto something with the fixed price tab at the top of the page as I have never done eBay sales this way I never took notice to that tab!

I don't either Taz. Just for the store. I rarely use BIN, just because it works better for me. The ones I've done were total duds and shouldn't have been. I know some sellers swear by it and have great results.

Thank you. I hadn't selected Fixed price at the top of the page.