@yukimine
1. I would say its very safe, theres a chance that you will be taken advantage of, in the sense of doing very hard work etc. In the case of being female most of the wwoofers I met were female and none of them said they had any bad experiences with it. What I can do if you are really unsure is recommend the place that I went. Its hard work but you get to experience alot and you will be around nice people, as the owner would not allow any nasty people to stay.
2. This is hard to say as I didnt keep tabs on my spendage but I would say I ended up spending around 35,000 yen in 3 months. But I did go travaling for a bit and I liked to get extra things (£80 worth of sake!). Its very possible to not spend anything, certainly if you go to the more remote places as there wont even be a chance to spend it
The hosts I have been with were quite generous and did pay for special things every now and agian. I even got given 10,000 when I left one host as a thank you.
3. Tips, oo thats a hard one.
Make a list of wwoof hosts that you are interested in and write down all their details on paper before you go. This is due to: If you don't like where you are you can quickly move on to somewhere new. Writing it down on paper makes it more convienant if you are at a place without the internet
This isnt a wwoof specific one but i will recommend it whenever I can!
For the love of god write down the details where you will be staying first and keep it where you can easily access it before boarding the plane to Japan. Japanese Immergration doesn't like you not having the details to hand.. They held me up for over 40 minutes due to me not doing this. (this may just be common sense on most peoples part.. but I wish I knew that before leaving)
I really am struggling to think of tips so I will add more later if any come to mind.
Feel free to ask as many questions as you want. I want to endorse how great wwoofing is!
*EDIT*
@Fuamnach
Oh god yes. My first place was basically 100% Japanese with me going a month without seeing any foreigners. It was so rare to get foreigners there that people would point at me, cross the street if they are heading towards me on the same path, children would chase after me and hide behind lamposts and watch me etc etc (maybe its just me!)
My second place (the one with the losts of english and americans) we were still surrounded by Japanese. Japanese farmers would often visit us and try to talk to us. Locals would wonder what we were doing and try to talk to us. We were invited to a town meeting when lots and lots of Japanese tried to talk to us. The list can just go on.
So basically yes lots and lots of chances to speak Japanese. You could even pick wwoof hosts that dont speak english which are much more common than hosts that speak english, ofcourse.
Edited: 2010-03-11, 7:24 pm