I went to TGS in 2009. It was a great experience, and the first time I was in Japan. I probably had the single greatest day of my life on that TGS Saturday due in part to everything else that happened that day, but that's another story entirely.
I'm not sure about travel agents/websites as I tend to just use Expedia when bouncing between countries over here, but my one bit of advice for anyone flying long distance is to ensure that you don't book direct flights to/from the UK, otherwise you get hit by an £50-80 tax charge.
As in:
- Last year I flew from Taipei to Edinburgh (with 2 stops in-between.)
- Buying a return ticket for Taipei to Edinburgh would have incurred the aforementioned tax due to long-distance flights originating/arriving in the UK.
- So instead I booked return tickets from Taipei to Amsterdam and another return ticket from Amsterdam to Edinburgh.
- This saved me £80. The ironic shit being that I would have been passing through Amsterdam Airport through both tickets.
Save up a decent cut of money from here until September and you should be fine. Tokyo is more expensive than the UK, Hong Kong is about on-par, but Seoul and Taipei are a lot cheaper than the UK in my experiences.