UK how much to spend on a wedding gift (from list)

Hello,
this is rather urgent - for me...
Could somebody please tell me fast (wedding next Saturday) how much you are supposed to spend on a wedding gift chosen from a wedding-list? It´s in the country-side, East of England, and not a high society-wedding, I think (but university graduates), reception in the local pub. Doesn´t have to be a fixed figure, I just need an idea (a range), for a normal invited person (not a very close friend), and/or for the maid of honour/witness, which would make a difference, I suppose.