PA38 can be purchased for approx 2/3 the price of a C152. The C152 is the better aeroplane. The C152 has no lifed parts other than the engine and the throttle cable. The PA38 has larger fuel tanks as standard although they did produced C152 with the optional long range tanks but they both will suffer from a very poor payload if the tanks are full. The PA38 has many ADs and is not good off a short runway. The biggest thing that determines the value is the engine life left. An engine overhaul will be in the region of £15,000. You might get lucky and operate it well into extension. Remember you will need an 8.33 radio after the 1st January. Both aeroplanes are great fun to fly and the chances are you can sell them again for what you paid. Make sure you get an independent survey done by an engineer prior to purchase. Good luck.