Manual that much of a burden? Default here.
Anyway budget, insurance budget, repairs budget and your technical aptitude (you can do an awful lot yourself, even more these days with the benefits of the internet, though at the same time more modern stuff also needs more and more fancy computer to do just about anything) or maybe that of your immediate circle (if your uncle is a mechanic and will keep you sorted then yeah). Equally do you want something sporty, able to haul stuff, any kind of offroad options, something able to be camped in, or just able to get you and a few bin bags worth of stuff from A to B?
I don't need to do state but if you are going to be somewhere salty, somewhere snowy or somewhere with other more extreme conditions we might wish to consider that. Similarly city driving, serious motorway/highway or living on a farm down a dirt track that knackers your suspension going up and down in several times a day?
Back on the technical thing do you know someone that can assess a vehicle for you and be in your corner? If you are asking this I am assuming you can't but if you have a family friend/relation able to look things over that will dodge a lot of headaches down the road (assuming you even get that far). They might also open up options like car auctions (if you are not a or with a mechanic I would not do them). Also there is a reason car dealerships are known as stealerships, and those specialising in second hand are worse than that. Though I am seeing some places have an actual price on the windscreen stateside these days and this whole kung flu lark is seeing some fairly tumultuous times for the car market (sadly this does mean second hand prices are going to be a bit strange -- demand for new is down, second hand is up, and there are lots of old lease cars also piling up).
Your area will also change what goes -- I have been around for car buying in a decent chunk of the US and helped in a few others. What you can find locally in LA is rather different to Seattle which is rather different to east of the mountains in the northwest, which is rather different to New Mexico (car theft is also a fairly popular hobby there) which is rather different to Texas which in turn differs massively within itself (oil fields are a fun one) and New York sees an awful lot of people do without a car.
Finally think long and hard before buying something from a friend/relative. If it is someone that knows their stuff, wants you to have something good and offers a good deal then OK, if it is going to be clueless person to clueless person and you have to sit around the Christmas table with them then better hope it was not a dud. On the other hand if grandma is being shuffled into a home or off this mortal coil then her nice old car she got serviced at the dealer with most of the distance being to bingo once a week then you can get something very nice there. Do note about 95% of mechanics treat their personal vehicles like crap and keep them barely roadworthy so buying your mechanic uncle's old beater might not be the best plan, even if having them with you to look at things would be.
Diesel or petrol (electric might be a bit much at this point, though some older hybrid stuff could do, though if your budget is it then it is an option, though you might also have to retrofit your house)?
Will you be becoming a pizza boy or some other delivery type setup? This would mean far more distance and wear on the vehicle which would factor into running and repair costs.
How long do you plan on keeping it? If it is going to be an earning my own money in two or three years and can get something nicer then that is one thing but if you want to do something now and run it into the ground over the next 8-10 years then that changes thing.
Equally is it a car for the sake of having a car in case you need one but otherwise you can walk/pedal/public transport around, might you instead consider a motorbike for some purposes or are we back to the farm in the middle of nowhere where a car is a necessity?
For the most part this then gives you a split between
Small hatchback car. These can get pretty nippy as well if you want. No chance of moving seriously in one (though if you can live that live then great), camping in one or hauling sheets of wood around. Usually quite cheap to buy, own and repair as well.
Mid size estate-sedan type thing. Can go sporty but can go basic. Depending upon what you get a decent haulage option and able to camp out of an evening. Price wise go from cheap to hideously expensive.
Pickup and these days I am also seeing work vans be a thing in the US where they were not so much before (here I know loads with a transit or similar as a daily). Great for hauling and can be converted to do a bit of sleeping as well on nicer nights. Be careful with insurance though as some insurance carriers will not entertain someone as young as you driving one.
People carrier/minivan. Assuming you are going to get a proper ticket to drive it (some states I see nonsense like can't have more than 2 friends after dark or whatever) never underestimate the storage capacity and ease of use of a vehicle that a suburban housewife used to nip to the shops, do the school run and the like babying it the whole way vs something in the above categories someone got as their first/early car and spent the subsequent next few years ragging around, learning to do j turns/handbrake turns and burnouts in.
The whole SUV thing seems to be dying off in some ways but there are plenty out there. I don't much like them to crash, repair, cart stuff around in, drive (though some can be fun if you want to have it) or fuel but eh. That said the range is wide from "almost a jeep" to stuff like the ford exploderrer which is more what I would look at in the people carrier thing above even if they brand it a SUV.