Is it true that prepaid phones are sold in combini's in Japan? Also, help on getting a prepaid phone?

Question:

Hey there,
I am an exchange student currently living in Sagamihara/Zama, Kanagawa, Japan. I've burned a hole in the web researching this but no one seems to have the exact answers that I want.

So yes, I do have a "Alien Resgistration" card, yes I will be here for more than 90 days. 7 more months infact. Although I am under 20, I am 18, my host parents are there to do all the signing for me. Should be easy right, just ask them. No such luck, they're old and know less about it than I do.
So my following question is. Where exactly can I buy a prepaid phone? Yeah, I know the softbank shops in Shinjuku and Riponngi etc. But I've heard you can buy them from electronic stores and funnily enough I heard the combini 'Lawson' and several sells them. I just wanna know if this is true? I have never seen them there, and I don't feel like dragging the old people all the way to Tokyo just to find out that the phones are outta stock. Also, the web is very elusive on giving me an estimate for the price of the phone. Yeah I know it's 3000yen for the credit to put on the phone but how much would the minimalistic clamshell Softbank 740sc cost? Any one who has recently bought one could they please explain where, how much they got the phone for.

Any speedy answers would be greatly appreciated as I really wanna get this sorted by this weekend.
Thanks if advance.

Answer:

Hi,
Most of cell phone carriers in Japan have already terminated their prepaid mobile phone services, because of their frequent use in crimes. Now au and SoftBank Mobile are the only carriers that still offer the service.
It's true that SoftBank used to sell their prepaid mobile phones (yes, the phones themselves, not the prepaid cards) in convenience stores, but they don't do that anymore.

Here are their official websites in English, where you can find where to buy such phones and where to ask questions.

SoftBank:
http://mb.softbank.jp/en/prepaid_service…
http://mb.softbank.jp/en/customer_suppor…

au:
http://www.au.kddi.com/english/seihin/pr…
http://www.au.kddi.com/english/customer/…

Hope that helps and you'll enjoy Japan! :)