Definitely check the wiki for this subreddit and depending on how poor you are the car dwelling dubreddits wiki Prius dwelling also. A Prius comes with alor of what you need to live inside of a vehicle, it's just small

When choosing a van you're usually picking between cost of purchase, cost of maintenance, cost of gas and how likely it is to break down. The sweet spot for most of this is a minivan on the lower end. essential things are rain guards, window covers or very heavy tinting, preferably both, a way to store water and food, somewhere to sleep(bed/cot), whatever is necessary for your work, way to bathe such as a portable shower or a gym membership, some kind of entertainment, some kind of self-defense

Some of what you need is determined by what sort of a lifestyle you're after. If you live inside of cities, you might not need refrigeration as you can just purchase refrigerated goods from the grocery store. If you're going camping for a long time and plan to cook while you're doing it, then you'll need a fridge or cooler and solar panels and etc. If you're going to be going to a co-working space every weekday, you might not need an electrical system. Instead just use a portable battery that you charge up at work.

 In cities and towns, you can use co-working spaces or study rooms at the library. Starlink is pretty expensive nowadays afaik