We buy store brands much of the time. We'll almost always give them a try, and if unsatisfactory, we'll go with the name brand. However, the store brand is usually just fine.
My sister has a friend who grew up really poor, and it's interesting to me that he scorns store brands completely, and seems to consider it almost a point of pride that he only eats Welch's grape jelly, Skippy peanut butter, etc. He is still very poor, and this attitude probably doesn't help matters any.