Use cheap power bank jump starter

Jump starters are more for emergency use. It'd be better to preserve your battery's charge, with either an appropriate amperage smart charger, connected before you go, or if that's not practical, just disconnect it, to avoid "phantom loads" the car imposes.

 

the 12v only closes relays and boots up computers to make he hybrid system 'ready'.
then the hybrid battery starts the engine as needed. the cheapest jump pack you can find will work, but every time you let the battery die, you reduce the life and run the risk of killing it altogether.

 

A few people have measured the current while starting a Prius using a 'scope—here's one—kinda showing a startup lasting 2½ seconds or so, with a current draw that kind of bounces around 20 amps, with a couple very brief spikes to 40 or 50 and one as high as 100. That's all still well within what any jump pack can give you.



It's good also to consider the total energy needed, as the smallest jump packs don't hold a whole lot. The taller spikes are so narrow I'm still going to say that curve just bounces around 20 amps for the most part, and 2½ seconds of that at 12 volts comes to 600 watt seconds, or 10 watt minutes. Or a sixth of a watt hour.

The last little jump pack I had would hold 29.6 watt hours. So even that tiny jump pack would be enough in theory to start a Prius over and over.

Except ...

What happens if you've forgotten you had the lights and heater and wipers on the last time you turned the car off? They'll use a bunch more of the juice from the jump pack than gets used just to start the hybrid system. Same for the brake pressure pump.

Moreover ...

Usually the reason you're trying to jump a Prius is because there's a severely discharged 12 volt battery in it. A severely discharged car battery can suck all the juice out of a 30 watt hour jump pack in the seconds it takes you to try pushing the start button and not even burp, and there you are seeing zero segments lit up on your jump pack and thinking "funny, I thought that was fully charged" and the car still isn't started.

There are ways to try to skate around all those things and successfully jump the car with a small pack, but they're easy to forget in the moment.

 

I would consider preparing the car at home for easy access to the 12v, and applying the jump pack under the hood for access to the hatch upon return

 

I would consider leaving the car at home connected to a battery charger and catching a train, bus, or Uber to the airport.