Airport parking, especially on-site parking can be expensive.  For a one or two night stay, you might want to spend the $25-$30 fee to park directly at the airport.  But if on a 2-4 trip, that would wind up to be about $750.   Look at The Traveling Professor's tip and save on parking your car at the airport. 

In determining the savings on parking, sometimes it is best to start with the cost of parking on-site, then look at the alternatives, and determine the savings vs. convenience.

Let's base it on a 2-week trip where parking would be $25 at a major airport.  That would mean parking would be $350.

Go Off-Site:  An obvious choice that would save 30%-50%.  However, one needs to consider the inconvenience of taking a shuttle back and forth to the airport.  For a bit better savings, most off-site parking facilities have discounts for joining their member award programs.

Uber:  Instead of driving to the airport and parking, we used Uber at a $50 one-way trip to the airport.  That was easy, but probably not worth it for a 2-3 day trip. Check Uber (or Lyft) out.  It might be surprising how inexpensive they are to travel to the airport, even if going a hundred miles or so.

Take the Train:  In our area, we can park 50 miles north of New York at the commuter parking lot for about $6 a day with weekends and holidays free.  We take the train into the city and transfer to the airport.  This saves a lot of money but there is an inconvenience factor there.

Stay at a Hotel:  We have been using this more and more.  For example, our hotel in Boston charges $200 a night for a room and let's us park our car an unlimited amount of nights. On our upcoming 28-day trip, that's a bargain, especially since we have a place to stay arriving late at night before our 3-hour drive home.  When flying out of JFK, we stay in a wonderful Homewood Suites about 25 miles to the airport at $165 for a night (with unlimited parking) and take the $32 Uber to the airport.  It is important to note that these park-and-fly rates are not advertised at the hotel.  We needed to call the hotel to make these arrangements. Also, a park-and-fly can be done where the traveler stays at the hotel then flies, or do a reverse park-and-fly where the traveler drops the car, flies, then stays at the hotel on the return.