Here comes some of the Sisters’ teachings from my childhood - along with good sense and my own opinion.
Yes, **buying on Sunday is a sin **- unless it’s an emergency: For instance, you have a baby and unexpectedly ran out of milk / Pampers, etc. (not planned - but unexpected). **Working on Sunday is a sin **- unless you’re in the medical (or similar) profession and can’t get that day off - but in my opinion you should make the request first to get Sunday off, if possible. (I work in a non-medical job where I have been asked to work on Sunday. It is NOT a necessity type of work, such as medical, and if they ever fire me for it - I will have to give up the job. I realize that sounds crazy in this economy - but I always remember the words, "For what does it profit a man, if he gains the whole world, but loses his own soul?"
Ironically, the one thing I DO buy on Sundays is the Sunday paper. I don’t like doing it and wonder if that’s a sin - but when else can you get the Sunday paper? Having it delivered, you’re buying it anyway - and encouraging someone else to work delivering it. Same thing when there’s a Church sale or Feast on a Sunday.