okay, Apple has charged me now after 48 hours.
Basically, from what I understood... Apple keeps the order "opened" for a while so that one can "batch" purchase more stuff.. and then charges together. I purchased an app named Linkinus for $10 yesterday. (i.e. one day after Mountain Lion [$20]).
Now I have been charged $30 together.
Apple still hasn't sent me an e-mail though.
Yep! I also haven't received iTunes receipt for various purchases (not in-app)
Apple will raise an INVOICE only when the purchase amount is above $20. They will club various small purchases under a single INVOICE until the total amount totals to more then $20.
To see your INVOICE do the following:
Step 1 : Open iTunes
Step 2 : Select the iTunes Store in the left side bar
Step 3 : Once the Store loads up hover your mouse on your account name [ top right corner ] you will see a arrow icon, click on the arrow icon and a drop down will popup.
Step 4 : Select
Account
Step 5 : Enter your Store Password in the popup that appears and click OK
Step 6 : Scroll to
Purchase History and select
See All
Step 7 : All your invoices, and billing information will be displayed.
Note : Purchase History is not your Receipt. If you need one, you will have to visit the Apple Physical Store, they will print the receipt for you.