We handed over a cheque for £10,500 last October and the PTA have NO SAY AT ALL on how it is spent!
We did try to change this a couple of years ago so we could work with teachers and get a wish list but the HT refused to let us and said that she would not go 'cap in hand to the PTA whenever she wanted cash!' 
This has irritated us but she is retiring in July and we hope to change the way things are done ifWeCanGetRidofTheEvilBursarToo
Just wondered how you do it in your school...............