We were advised by the British Council to bring €1000-€1500 with us to get set up on our placement year (in Germany 2007-8) as you can't be too sure when your first pay packet will go in and you need to get a place to live etc. Travel costs will really depend where you go, but just as you would for a holiday, shop around to get the cheapest you can. I think I used to get €30-€60 returns between Birmingham/Gatwick and Cologne with Easyjet or TuiFly, but it did get into the €100s around Christmas and New Year.