A four-character idiom meaning extremely cheap; worth very little.
古本屋でこの百科事典は二束三文で売られていた。
This encyclopedia was being sold for next to nothing at the used bookstore.
品質の悪い偽物は二束三文にしかならない。
Poor-quality fakes are only worth a pittance.
あの業者に売れば、時計は二束三文だろう。
If you sell to that dealer, the watch will fetch next to nothing.