1 - Train.
Take the Train from Banbury, Bicester North or Thame. Parking at the stations are £5.50 per day and off-peak tickets pretty decent. You can park around the stations to save you some ca$h , but will no doubt piss off locals
![Smile :-)](./images/smilies/icon_smile.gif)
Coming back is hellish though, expect Alton Towers style queues.
2 - Coach
Oxford Tube or Bus Company -Option 1 Get off at Hillingdon and take the Metropolitan line and get off at Wembley Park. Hilliingdon to Wembley is about 40mins. Also check the TFL website for weekend works.
Option 2 (if you are on the 190, Oxford Tube does not stop here) get off at Baker street and Walk to Marylebone. It's 5 mins if that. Chiltern will be running special Wembley trains all day. It's 15mins from there to Wembley Stadium
3-Car Check local NCP or car parking sites near tube stations on the lines to Wembley. Way cheaper than Wembley car parking and local tubes should be less busy than the trains. Again check TFL for news.
Jubilee line is kaput on weekends, do not plan to use it at all.
Hope this helps!