I agree that the EU is better than the US for such an event (look at total area and populations). I don't know about the US, but the major cities in europe are connected by cheap flights (e.g. easy-jet, ryan air, wizz, german wings,...) If you book them early enough, you might get the flight for about 20-30€ (one way). At least that would be the price for flights from Budapest to London (Luton). then you'd have to take the train, but it could be more expensive Oo.
I won't be coming, since I don't know where I'll end up (possibilities range from anywhere in germany, to Budapest, Szeged or pecs and riga), so I can't plan, and I don't know when university starts either^^