If I would like to purchase grapes, but only want $5 worth, not

Lower Township - If I would like to purchase grapes, but only want $5 worth, not $12, what should I do? I suppose I should take out some grapes, weigh the bag and proceed. Or should I spend the $5 at a fast food establishment and get diabetes? So sorry I touched the grapes. How about stores don't stuff the bag so full for families on a budget?