Swimming is the cheapest, and apparently not impossible as more than 1000 people already did it before you.
But let's say you are not adventurous and want to use a more conventional type of transport. You could fly of course, but the price would be high and the time lost quite substantial. First you need to go to the airport, then arrive 2 hours in advance. Once you touch down in any of the English airports you would have a long custom control to go through and spend at least an hour on the Tube (that is the London Metro/Subway).
No, by train is more logical. You can take the Eurostar if you are traveling on foot, or the Eurotunnel if you want to put your car in a cattle wagon-style vehicle. Both options will only take 30 minutes, but you need to check in on time and in the case of the Eurostar you'll need to get to the train station. Big advantage is that you will be dropped in the middle of London (Waterloo Station) or in the case of the Eurotunnel in Ashford.
A last alternative (and one I tried this month) is taking a ferry from Dunkirk or Calais to Dover. There are a number of companies that organise 90-minute ferry services and we opted for DFDS Seaways. They had a great offer at only 54 euro return for one car and up to 9 passengers (not sure how I could fit 9 passengers in a small Renault Scenic). The advertise with the promise that you will get a premium service at a low price, but only part of that promise is true. They are cheap, yes, but the service is not special and the condition of their ships are not so good. Lots of broken chairs, stained carpets, several decks that were closed and an overpriced shop and cafetaria.
But beggars can't be choosers and it's still great value for money. No hassle, just order online, fill in some details and before you know it you'll have your booking reference which is the only thing you'll need on the day of sailing. If you want to check them out: DFDS Seaways
