As @Pranjal says…
Plus, the Man-Math involved is usually pretty personal and complex.
I know I came from a big old barge of an ICE (averaging <24mpg of petrol and imminently ready for £1k+ bills) in which I had mileage going from 7k pre pandemic down to 3k… which is getting to be ridiculous in terms of car ownership.
In only 4 ½ months with Onto I’ve already exceeded 5k miles 

because of a set of circumstances such as EVs are so much fun to drive, I don’t feel so “guilty” about polluting the planet and I’m off many days looking for somewhere new to get my daily walk…
So take care in estimating your expected mileage
but consider that and whether you’re coming to Onto for one month or medium-term, then you can see those delivery charges in context.
Also, swapping is not the full delivery cost and would be subsidised a little bit by any reward (sort-of-monthly-loyalty-points) you build - or indeed extra mileage to suit your needs! So, if your motivation were say (as is mine) to try 3 cars over a year it will be a whole different proposition than a one month “rental”….
So: mileage expected? which car? time horizon?
Whichever way, welcome to the community! 
Edited to add: took so long with my reply
… yes - everything is more expensive this year, and it is hitting the lowest priced cars hardest 