There has been a fairly recent thread on this, but I'm hopeless at finding old threads.
Basically, anything with dial-up (synthesised) tuning should be OK. A dial with a string moving a pointer across the scale will NOT do the job.
There are receivers around the £80 mark that will do the job - for example, go to
http://www.wsplc.com/ click "Products", "Airband", "Airband Receivers".
Any of the Maycoms or the Yupiteru would do the job for you.
BUT if you are going to get a PPL and fly regularly, I'd go for a transceiver NOW. The Icom is the one I'd choose. Indeed, the one I did choose, and use quite a bit. Saves a lot of palaver calling for startup clearance at those places where you need to.