Paizo - as a rule - doesn't bill until items ship.
That said, some things if you order there can be a short-term funds hold as the credit system confirms funds are available. That's generally a few hours to a day. It's not unlike going to a gas station to pump gas and the pump puts a temporary hold on funds for a few minutes while you pump, then processes the final transaction.
For items not shipping until August, you should have no issues.
Hello Chris,
Anguish has it correct. We only charge for the items once they ship. However, when you submit the order, our system will ping your bank to ensure that the card information is good and the card has the funds it will need to process the transaction later. At that point most banks place a temporary hold on those funds that will release a day or two after it appears.
For Second Edition materials, it is most likely that you will see a finalized charge for the order between sometime July 8th-August 1st.