Ticket prices are high because they are only allowing 50,000 spectators (according to a report I read somewhere - forget where now...)
Having said that - grandstand seats at the British GP just for the Sunday were £200 - and that was to sit in the bloody p!ssing rain, freezing cold, to catch the occasional glimps of a car through the spray!
Couldnt see anything at the start - but still worth it to see Hamilton win, had to keep calling home to find out what was happening though, as you couldnt see one of the big screens