More free credit
Reader "Tokyo Angel" got a no-charge credit card after hunting around for a while. She currently has a Nicos Visa card through the post office (application forms are available from all post offices) that has no annual fee and which includes full travel insurance aswell, even if you don't pay for your trip with the card.
There's a list of other services on the yahoo.co.jp site though only in Japanese. This is a great reference site because it includes all their other perks as well, so it's easy to compare the different companies and you can also apply for an application form online (only in Japanese again).
Tokyo Angel found a host of no-charge cards through the Yahoo site, including an NTT card (Visa); DC card Jizile (Visa); Arubara card (JCB); Japan Postal Savings card (Visa); Nicos Japan Postal Savings card (Visa); and an Aeon card (Visa).