I think at this price level, the most important factor is condition and provable service history. The interior of a car often gives a better clue as to how well a car has been looked after. Buy from a known garage to protect yourself under the Sale of Goods act. Do your research, try and find old bills/invoices, speak to the previous owner(s), and take it on a proper test drive, at least 10 miles, not just round the block.

The previous model Fiesta falls into this price bracket, you could do a lot worse in terms of parts prices and cheap to fix.

You could look for a Yaris or Micra, older shape Fabia, or indeed another Polo.

But Condition is more important than model.

First generation Mazda 2 (2003-07). Third member of Fiesta/Fusion family.