If you live in Europe and plan couple months ahead you can buy international flights with Ryanair or any other budget airline for as little as $50, round trip. So it's perfectly possible for a student to go for a weekend in Paris or London, staying at youth hostels or AirBnB locations. If you don't mind taking a bus it's even cheaper, my friends just booked a bus to London(from North of England, so not quite international, but still) for $7 because they booked it 4 months in advance and the bus leaves at 1am so it's not very popular.