There are plenty of PT Cruisers on the second hand market but it is best avoiding early cars unless you're on a tight budget. The 2.2 CRD is the best engine to go for (particularly the more powerful version introduced in 2006) but the 2.4-litre isn't too bad for economy if you won't be covering large mileages. There are a few in car supermarkets but it's not as fashionable as it once was.
When it was first launched the PT Cruiser caused quite a fuss, but it hasn't aged particularly well. Still, it makes a usefully practical and unusual buy while buyers will value well specified diesel models the most. The limited edition models may get you a slight premium - but only among PT Cruiser enthusiasts.