Once an order is placed online, a pending authorization (temporary hold of funds) for the full amount of the purchase will reflect on the form of payment but no funds are taken until the items are shipped.
Please note, sometimes orders are shipped in multiple packages and this might cause multiple, smaller posts on your bank statement for your single order.
Pending authorizations will show on your account as a "pending charge" and will clear on its own between 1-8 business days for debit cards. Credit card holds may last as long as 30 days, depending on your bank.