If rookies has a VISA Debit card they'll accept that too
VISA Debit works just like a credit card in that you can use it for online purchases but it draws on funds already in the balance, so you're more in control of what you spend.
Also, depending on where you live, you can use
Avex Taiwan, which sells the TW presses of its releases. The downside is that you have to be in Taiwan to order.
Play-Asia also sells music including J-Pop. They don't stock MANY OS versions, but you will find some on there. Most of the bigger artists always have OS presses there too