Flight Price Monitoring: There are several flight price trackers, such as Kayak, Airfarewatchdog, Google Flights, and Hopper. The problem is none of them can guarantee up-to-date info. For example, Hopper one day showed prices slashed 75% on a trip to Paris that did not show up on any of the others. So, this is one service where more is more and the more the merrier.
Turo: Just as Airbnb can help you find inexpensive lodging, Turo lets you rent cars from individuals -- often for significantly less money than (even half or more what) you'd pay a rental service. Just choose your dates and location to see what's available and for how much. Another nice perk: You know exactly what kind of car you're getting, rather than the vague "midsize sedan" kind of description you get with typical rentals. Of course, as with Airbnb, you'll want to check the lender's ratings first, and also investigate insurance options. (Don't assume your credit card will cover you.)
[Courtesy in part to cnet]