Picanto, Twingo, C1 & Co…. alternatives or best solution up to 6000 EUR

Hello forists, for my mother I am looking for a small or small car. There are 6000,- EUR available, which can be invested to the best of my knowledge. On top could come at most the yield from the utilization of the existing Opel Corsa B: 16 years old, HU until 03.2016 and the servo is ready, the colleague rust hovers over the vehicle like the vultures over the car. Already examined were C1 5-door (2011/2012), Picanto (2014/2015), Twingo (2010-2013). The Twingo will also fall out of the previously not mentioned Chevrolet Spark: here I lack a quality impression. Dacia is not a topic, please don’t make any suggestions about it. Nor will a smart one. In the budget you will already get a few older Clio or Corsa, which would not be necessary from the desired and required greetings. Except for a radio my mother wants as little equipment as possible. Climate can be, but does not have to be. The C1 would be good, however The Picanto fits so far, unfortunately we get for the desired budget only the “old” model and not the current one, which likes very much. Also the sitting position here is very important. It would be possible if necessary also the increase of the budget, but then it must be a “real” profit, e.g. new car / day registration or something special, that the others can not offer. I would be very pleased about suggestions, suggestions, since me in the usual booty scheme is a completely different one. Thank you in advance…