To get from England to continental Europe there are a few options. We chose to go over via boat on the Stena Line ferry. On Thursday night we got a train from London to Harwich, and from there we got a ferry to Hook of Holland.
For us, this was the most economical option, though it seems to be the least common one. From what I can tell, most people now fly over on a budget airline, which can indeed be an amazing deal. When I checked for flights from London to Berlin, for example, I found fares starting at €10. I was shocked. But by the time all the taxes and fees were added up the tickets actually cost around €100, per person. To that price we would have had to add transportation costs to (usually remote) airports, as well as a hostel/hotel when we arrived.
Instead, we got a “rail and sail” ticket across for £148 for both of us. It includes a train ticket from London’s Liverpool Station, a ferry ride to Holland and, perhaps best of all, a cabin to sleep in. Because of those things we did the trip mostly at night when we would otherwise be sleeping. That saved us from having to pay for lodging.
(There is also the option to cross the English Channel via train/Chunnel. While I would have liked to experienced that, it also was more expensive than the ferry.)
The ferry itself was quite a bit grander than we had anticipated. The cabin that we got was nicer than the hotels we’ve stayed in, and it was larger than our room a easyHotel. It had bunk beds, a couch, TV, and free wireless Internet. There were also several restaurants inboard and some nice-ish lounges. We didn’t really take advantage of most of these things because we slept through the ride, but on the whole the ferry was nicer, even swankier, than we had anticipated. One of the only disadvantages was that the actual trip isn’t that long, so while we slept well, we didn’t sleep that much.
When we arrived in Holland we used our rail tickets (which we part of the deal with the ferry company), to get to Amsterdam.