I’ve never taken a taxi to or from the airport, so I’m no help here. In town taxis are readily available and they seem to have a rate card instead of meters. Within the Cabo San Lucas hotel zone nearly every ride seems to be $9 (they want to make sure they get that $1 tip). If you leave the hotel zone prices seem to get go up quickly. I believe I once paid about $30 to go from the Medano Beach area to Sunset Mona Lisa.
You could book a shared airport shuttle for around $13–25/person (depending on where your hotel is) but at this point you will be excited to get your vacation started and if you are staying down in Cabo San Lucas the shuttle will make several (very annoying) stops to drop off other passengers first. Therefore, if you are not renting a car I suggest you take a private car.
A private Suburban from Hostransfer will cost $150.00 round trip (I also tip $20 each way) and will get you a very nice air conditioned private ride from and to the airport for up to six people. The big advantage here is that your driver will stop and wait while you get groceries and supplies.
Another great advantage of a private car over the shared shuttle is that on your way out of town the shared shuttle often wants to pick you up at least 4 hours before your flight since you will have to make all the same extra stops to pick up others on your way to the airport.
Driving in Mexico is not as scary as one might think, especially if you avoid the dense areas of “downtown” Cabo San Lucas, and if you want the ability to get away from the hotel you shouldn’t hesitate to rent a car for your trip. Most hotels do not charge you to park overnight but you may want to ask and you may want to be prepared to tip the valets if they handle the parking at your hotel.
The Yelp reviews of most car rental companies in Cabo are awful and my experience with one of the big US chains matched the awful reviews. The price I ended up paying was double what the reservation I booked online said it would be. Much of the price difference was because I chose to add liability coverage since my US auto insurance provided no coverage in Mexico. (Many higher-end credit cards such as American Express Platinum, Chase Sapphire Reserve, and even the Citi Costco Anywhere Visa include damage coverage, but not liability, when you decline the rental company’s collision loss/damage insurance.)
There are a few toll roads around Cabo, including the main route between the airport and Cabo San Lucas, so be prepared to pay the ~$3 toll. The toll takers will accept pesos or US dollars.
If you don’t have cellular data be sure to grab some maps from the rental agency because you won’t want to use Waze or Apple Maps without an International data plan.