prepaid mobile

I know gaijins cant buy prepaid mobile phones in Japan without an alien registration card but I was wondering how much a prepaid mobile was worth to purchase. I could get a friend to oragnise me one before I get there under her name. I dont need it to do anything exciting and it doesnt need to be top of the range. I would just prefer to own my own as I travel to Japan regularly and I have little kids so the chance of it being played with is (and possibley dropped or broken) high (and then I would only get charged to purchase by the rental firm anyway).

They don't seem to list prices on their sites (for example: http://mb.softbank.jp/mb/en/prepaid/)

I have purchased prepaids in the past, though, and they generally cost me from 6000 yen up.

Does that include any credit? What is the base amount of credit I could put on it to activate it? Was hoping to mainly use it for incoming calls and to keep in touch with a few friends while traveling around. Can u send messages/emails on a prepaid phone?

Does that include any credit?

No

What is the base amount of credit I could put on it to activate it?

3000 yen and 5000 yen cards are available. keep in mind that credit expires 60 days after activation, but your phone will remain active and able to receive calls up to 360 days after your credit expires.

Was hoping to mainly use it for incoming calls and to keep in touch with a few friends while traveling around. Can u send messages/emails on a prepaid phone?

yes, and note that softbank has a 300 yen per month unlimited sending charge.

details here:
http://mb.softbank.jp/mb/en/prepaid/3G/about/index.html

I was able to buy a prepaid without an alien registration card. I bought my softbank 822p from a Don Quijote. I think it was about 9000 yen and it came with a 3000 yen card. but no charger. They just asked for my passport, japanese address and foreign address.

get the unlimited msg for 300yen/month. calls are very expensive to make, but incoming is free.