We're often in a hurry when we run to the grocery store, which makes it tempting to buy pre-prepped ingredients that will get dinner on the table in a hurry. Here are the top things you shouldn't buy at the grocery store if you can help it. Credit: Getty ImagesBagged Salad KitsBagged salad kits are much more expensive than making your own when you consider the cost per serving. Bottled WaterMost bottled water is just repackaged tap water, so isn't necessary unless you don't have access to clean water. But it's a lot more economical to buy whole fruit and slice it yourself.