Hi I'm going to spend at least one month in dead sea from April to june 2013, im looking for a buddy to share the hotel room or hostel room in order to save money.
This is a little difficult. The only way I know is to post something on some site that helps people do what you want to do, and try to find someone looking for the same thing you are looking for. The great and obvious difficulty with that is that you could get Mother Theresa as a roommate, or an axe murderer. The question is how do you know???
Here's what I would suggest. There's a site www.janglo.net. It deals with all sorts of things that anglos are looking for in Israel. I would see if you could find someone who is looking for what you are looking for. Then I would ask them for some references. I would want at least two references not from regular people (they could be axe murderers themselves!). I would ask for references from two people like Rabbis or priests (if you're not Jewish and feel more comfortable that way). Then you want a Rabbi from an established synagogue, so that you can look up the synagogue on the internet and see that it exists, and that the name of the Rabbi that the person gives you is really the Rabbi at that synagogue. You could also do that with any other person in some authority in an institution that you can feel is an established one, and where you can verify that the name of the person is a real person, and you can write to him/her at the address on the internet. You then reduce the odds of rooming with an insane person dramatically (can you tell that I have two daughters????). You can also try to ask other people in this person's circle and get some idea of what they are like. The more information you gather the more you can rest your head comfortably that you've done the proper homework.
I hope this helps. There is also Craig's List in Israel, but I'd try Janglo first, and see what comes up. You may find some people on the Janglo site who can give you some other suggestions. Just remember that I think it's important to be able to verify what people are telling you.
Good luck, I hope it all works out for you!