When you start getting offers on an item you’re selling, you may see a Best Offer banner. It highlights the largest offer you’ve received on something that’s selling for a negotiable price. Use it as a guide to help you decide on an acceptable price and select a buyer.
To see if you have a high offer, go to 
Offers and tap Selling, then look for the banner on any of your items.
Note that this banner can’t be removed, but it’s visible only to you.