You need to buy a certain number of albums to get Aidou to sign for you. (For example, if a group has five members, there will be five one-page TO tags, one for each member).
Some rice can save yourself some money, so let's fight for it.
It means, for example, if you want a member's signature and want to buy 10 album, then what you finally receive is 10 album +A signed torn page signature.