Notes

• The Interrail price is based on the standard adult price for 4 days of travel within a month. It's cheaper if you're under 28 or over 59. Interrail details on their website here. But wait until January IF you have match tickets, as there is the promise of a discounted pass for ticket holders. If you're travelling without match tickets, you might as well buy a pass now.
   
• The asterisk beside Day 1* and Day 4* is just because I don't know if the tram between Edinburgh station and airport is covered by Interrail.
   
• The Deutschlandticket is a monthly subscription and covers all public transport throughout Germany, except express long-distance trains. €49 is the price for one calendar month. So, my suggestion is to buy this at the start of June and cancel it with effect as of midnight on 30th June (which you must do by 10th June). More details on the Deutsche Bahn website here.
   
• For the flights, I've assumed that your luggage for 2 weeks won't fit under your seat, so have added Ryanair's £27 per flight for a case to go in an overhead locker. If you can manage with a small bag, you can save £27 per flight. Ryanair website here.
   
• For each game, I've suggested accommodation away from the host city, so that the prices are lower. The places I've chosen are not the absolute cheapest. If you're happy with a hostel several miles from the town's train station, you could find cheaper.
   
• The accommodation prices shown are based on twin rooms and are per person.
   
• The hotel in Augsburg is the Ibis, very handy for the main station, from where it's 48 minutes to Munich (on a non-express train)
   
• The apartment in Siegburg, near Bonn is also not far from the station, from where it's 31 minutes to Cologne
   
• The hotel in Ludwigsburg is the NH, also very close to the station, from where you can reach Stuttgart in 12 minutes