We've got 3 of the Pooley's budget headsets in our School PA28. They stand up to the rough and tumble of trial lessons and students bashing them about and standing on them etc. You can get new gel cups for them if required and Pooleys will repair them if needed. I've tried them out and they seem perfectly good for wearing up to 3 - 4 hours a week.
I tried David Clark and couldn't get on with the high clamping force, so flew with a Peltor I bought from Transair when they first opened. They lasted nearly 20 years. When David Clark brought out their first ANR - the X11 - I invested in them as they seemed marginally better than the Bose at the time (10 years ago). They were horrible, but having spent all that money, I kept with them. I was really pleased when the carbon fibre headband snapped. I then invested in the Lightspeed Sierra. Absolutely brilliant, lovely ANR, Bluetooth for the phone, seem compatible with everything.
I'd say DON'T invest in a decent headset whilst training (unless you've got plenty of spare cash!) Spend the money on extra flight training instead, it'll reward you better. When you get your licence, that's the time to treat yourself.
TOO