There are a couple of sites that can save you big bucks the next time you need to park in a busy metro area or at an airport.

It's no secret that parking can be very expensive in metro areas. In fact, a tandem spot in Boston once sold at auction for $560,000!

That's why you have to think outside of the box...

Read more: These are the most and least expensive places to rent a car

Cheap parking is possible!

ParkWhiz.com is one website that lets you find private parking nearby many popular venues that are put up for bid and offered as deals based on demand and date. You can save more than 50% using this site. In one instance, Clark was looking for parking near a popular venue in his hometown. The official parking was $30, but he was seeing private parking on this app for $8 to $12. All it takes is a reservation in advance to save!

ParkingPanda.com is another site he's talked about in the past. Now they're in Albuquerque, Baltimore, Dallas, Houston, New Orleans, San Francisco, Washington, D.C., and select airports around the country. With this site, you also rent space in people's garages or driveways and save a lot of money.

Here are some other options to consider:

Pre-paid guaranteed parking apps

ParkMe
Available in 90,000+ locations, 4,200 cities, 7 continents

Parker
Shows the closest and cheapest open parking space in real-time, including parking lots and street parking.

SpotHero
More than 2,500 locations across the country. Plus, it offers monthly rates.

Best Parking
Available in 100+ cities and 115+ airports

Street parking

Smooth Parking
This is a cool website and app that shows where you will find free and metered street parking in your city. Enter the hours and location to see a real-time map.

Parkopedia
Parkopedia calls itself the Wikipedia of parking, showing parking maps and rates for 75 countries and over 6000 cities.

Airport parking

United Airport Parking
Airport parking (usually at large corporate hotels nearby) that gives you a place to park for the duration of your travels, and offers frequent shuttle service to the terminal -- at a fraction of  airport rates. Prices average about $2-3 day plus a $5 service fee.

Airport Parking Reservations
Airports and cruiseports in the U.S., Canada and UK

Read more: 9 apps that can make you extra money

A warning about unattended parking lots

There's a scourge going on around the country where you park at an unattended lot, pay the box, and come back to find your car booted or towed. Some parking lot operators don't want to install kiosks that would print out a receipt -- because there's a lot of money to be made from booting and towing your car!

Clark will not parked in an unattended private lot because he's heard too much bad stuff about them.

But there is one suggestion he has that can help you if you must park in an unattended lot: Take your smartphone and shoot a video of yourself paying the box.

You might also consider printing out some basic slips of paper on your home computer that say "I paid and I videotaped myself paying for it." Then keep these in the glove compartment for times when you have to park at an unattended lot.

Meanwhile, cities where this is a big problem should pass a regulation or ordinance that requires any unattended parking lot to have a kiosk that gives out payment receipts!

No smartphone? Use Uber and Lyft by phone