As the mom in my household, I don't typically ask for anything. (kids are still too small to think of anything on their own.) However, this year I have asked my husband for a clothesline. It's something we would buy anyway, as we moved to this house late last fall and are now ready to put one out. But I thought it would kill two birds with one stone if I just told him it could be a Mother's day gift.
As a daughter, I typically give my mothers and grandmothers hanging plants (usually found at Lowe's or Aldi for 5.99 and up) or a rose bush (around $5-10) I typically plant my grandmother's for her, if it's something that needs put in the ground. Bonus points for the extra time spent with her.