I agree with both of you, but it would seem OP isn’t a position to borrow money for a nice pair of boots, but just need to replace the replace the duct tape currently employed as footwear.

Other have said it too, but I’ll boil it down:

• Budget beaters are not on car apps. That’s mostly dealers, who will be making a profit.
• Buy from individuals. Use general second hand platforms instead, like facebook marketplace or what is used in your location.
• Be weary of private individuals flipping cars, they’re looking for profit like dealers, but will have done nothing in terms of maintenance beside the painfully obvious, which will have been a diy job with the cheapest parts available.
• Running costs are a PITA. Besides insurance and fuel you should look at what a set of tyres costs. For some reason that’s a somewhat decent indicator of maintenance costs level.
• Depending on periodic inspection rules in your country, buying a recently inspected car can mean you have a car for 2 years that you can discard afterwards, instead of sinking a shit loaf of money into maintenance ahead of the next inspection.
• Depending on where you live, cars can have been used as collateral for car loans. Typically not at your price point, but it’s something to be aware of. Buying a super cheap car, only to find out that it comes with 2 times it’s price in debt sucks.

What’s your budget? I mean I don’t think 10k € is a car for broke people, but are we talking 5k? 2k? I found a local Suzuki Wagon R+, 20years old, ugly AF faded paint, but a solid car with a couple of years left, listed for 13k DKK, that’s like 1700 €. I don’t think that you’ll have much luck finding cheaper cars than that.