As an example according the the Civil List of 2008 the Queen spent £66,749 on wines and spirits for receptions, personally I think this is a very low figure given all the functions that the Queen hosts

She should get the buggers to bring a bottle. Few of the people who attend the Queen's "receptions" are short of a bob or two. Here's me buying three for ten quid at Asda while she spends my dough on vintage champers for rich people. Something of a microcosm there...