This lettuce keeper. It keeps lettuce so fresh that your lettuce will actually taste crisper after spending 24 hours in here. I live alone and can buy the bag of 3 heads of romaine lettuce and it will make it last until the last piece.
It's less than $20 and will save you so much wasted produce. The lettuce actually gets "crisper" after being in there for a day and helps it stay fresh far longer than any other method I've used.