Chunnel ticket
I just booked a one-way from Paris to London in October with a first class seat for the price of coach - it was non-refundable and that's why the fare was discounted. It was ~$180 one-way; don't remember the round-trip fare. I don't recall if there were coach non-refundable tickets available at a lower price, but I'm traveling alone so I didn't mind the cost.
You have to pay $16 for the ticket to be delivered to you via UPS Express - that's the only way they'll deliver the tickets, you can't print them online.