expression, i-adjective
on very good terms; romantically involved
A set phrase literally meaning 'not cheap', used idiomatically to describe a close, often romantic, relationship. Typically used in the form お安くない仲 or お安くない関係.
あの二人はお安くない仲らしい。
Those two seem to be more than just friends.
彼らはお安くない関係だと噂されている。
They are rumored to be romantically involved.