It might seem like the obvious choice but another Kia Picanto would be a really good option. There aren't many small cars available with good torque-converter autos, but the Picanto is one of them. Your budget will get you a good 2015 or 2016 example. Also consider the very similar Hyundai i10 or, if you'd prefer something a little bigger, a Hyundai i20 or Vauxhall Corsa.