Which Commuter

OK, so I obviously need help finding a new car. I’m looking for the cheapest overall vehicle long-term that I will not have to repair often and has good-great gas mileage. I’m not worried about how cool it looks, or how much/fast you can rev the engine necessarily. Someone rear ended my 08 Honda Fit last year, I liked that car because it was small and easy to park. But also presented a minor challenge when buying 10ft 2x4s. Been looking at certified pre-owned corollas mainly, just because I don’t know much about cars and have other things Id rather spend time with than dozens of hours learning about them. (But will do enough to save money) I have enough saved up (very frugal) to buy a CPO corolla (2020-2023), but as I just said I’m very frugal and don’t like to spend a lot of money at a time. I’d like to try and stay around $15k-20k so I can put most of it down and only have a couple thousand in debt. (Also because I only have 1 CC it could build my credit.) this would still leave me with more than 6 months expenses saved and I wouldn’t worry so much about how I need to get back into the Dr., dentist, therapy, all of life’s other expenses blah blah blah. I need help. Is $15-20k a reasonable amount to be looking at in my position, Am I looking at the right car first-off, but also the correct years or should I try looking for a 2015-2019, hoping it lasts 5-10 years or more?(I’m single and 25, live alone)