This was a hardback picture book we read in the library in the 1980s. Two or three children go to a fair. On the way to or at the fair they get some small items (possibly a gold star?), which are put in a ‘cornucopia’. I think this was pictured as a paper cone. On the way home through the forest, robbers steal their treasures. I think it had the line ‘what wicked robbers to steal such precious things’, the point being these are items of no commercial value, but things of wonder to the children.