These days everyone has a smart phone in their hand. As of July 13, 2016 an estimate of over 15 million per day is playing the app Pokeman Go according to Recode.net. Fortunately, there are many useful apps that we can save time and money.
LifeHack.org has 15 terrific and some unusual apps. I have used Yerdle. I received a pair of almost new Nike shoes. It's fairly easy to shop and give away your unwanted things. Yerdle uses credits to buy things. You can pick up locally or have items shipped.
My sister lives in San Francisco and she would love the JustPark app. Sometimes she parks a mile away and still gets a ticket for not moving her car in time.
Would you share your leftovers? Me, personally, wasting food is a pet peeve of mine. If any of my co-workers have leftovers, I will gladly take it. When we have leftovers at home, we usually eat it the next day. LeftOverSwap might be a little too personal. But if you want to share it and meet new people, enjoy!