Apple also aggregates payments. I use my PayPal account (somehow that lets me avoid sales tax...who knows why...) for iTunes. Typically they'll bill me immediately for the first song (presumably to make sure my PayPal account still works), then they seem to aggregate anywhere from 1 day to 1 week worth of purchases up to about $30 before billing again.
They did this aggregation when I just had my plain old credit card number linked as well, although I don't think they ran the first charge immediately (probably just reserved funds).
They did this aggregation when I just had my plain old credit card number linked as well, although I don't think they ran the first charge immediately (probably just reserved funds).