I wanted to go on a trans-atlantic cruise but the one way return flight (Premium economy, I am too tall for regular 30" seat pitch) was $2000. Regular economy was closer to $600-$800. Not even round trip.
Unlike domestic flights, international flights are often priced as essentially round-trip only. In the sense that buying one-way is almost as expensive as round-trip.
I haven't yet figured out what the exact logic is behind this and when it applies; it's just been my personal experience.
