About 25 years ago or maybe longer my late Mother punched in mid August in the local market several boxes of Christmas cards. They were cheap. Upon getting them home she discovered the print error with each card reading 'Have a Christmas'. Without a word she promptly typed up 50 sticky labels with the word 'Happy' and stuck them in the cards with a little arrow so that they now read 'Have a Happy Christmas'. The next year saw a decrease in the amount of cards received by the Condor family. I wonder why?
At the back of the Trader Joe's I go to, there's a display with all kinds of cards - some are themed (b'day, holiday, etc.), some are blank inside with a nice picture / painting / graphic arts in front. For a buck you can't go wrong. I stock up.