1. Salad dressing. You can make a vinaigrette at home in less than a minute, by combining one part vinegar and three parts oil, then adding salt and pepper. Save calories, money, and most of the space on the inside of your refrigerator door.
2. Gift cards. You do it because you forgot to buy a gift and you're in a hurry. But the activation fees are $5 or more, even for a $50 card. You can get a gift card to the store itself with no activation fees.
3. Greeting cards. You spend $4 on one card and it's corny. You could buy 50 blank cards and envelopes from Amazon for $7, and write your own messages.
4. Name brand spices. Too expensive, and most people can't tell the difference. Get bulk spices from a health food store, or grow your own herbs in a window planter.
5. Flowers. The pre-made bouquets tend to wilt quickly, and they're filled with a lot of greenery and not enough actual flowers. You can save money by buying single flowers and making your own arrangement.
6. Party supplies. Just get them at the dollar store. You'll pay less than half as much, and they might even have a better selection.
7. Lunchables. They're REALLY unhealthy, especially the pepperoni pizza kind. It takes almost no time in the morning to make a sandwich for a school lunch. There's no reason to pay lots of money AND sacrifice your kids' health, just to save a few minutes.
8. Batteries. Groceries make them extra-expensive because they know you never think to buy them until you need them. You get a much better deal buying in bulk at Costco, or using rechargeables.
9. Bottled water. It's usually no safer than tap water, and it costs 1,000 times more. If you don't like the taste of tap water, get a Brita or a filter for your faucet. Then use stainless steel water bottles and keep refilling them.
10. Diapers. Again, there's a big markup because you usually don't buy them until you're out. Buy in bulk from Amazon or Costco, and save a lot of money.