Selling

According to this $0.

See this --> Apple Trade In - Apple

iPhone 6 Plus is an Obsolete model iPhone. It can't be updated to current iOS versions and is now VERY old. It really has no value at this point.

The iPhone 6+, released by Apple over eight years ago, is worth no money in trade. It will be accepted for recycling if you wish.

Apple Trade In - Apple

Zero.

I assume you mean trade it in. Its value is zero.

This isn't a bargaining situation. $0 is all Apple will give you. They'll be happy to recycle it. They won't give you ANY money for it.