Online banking allows you to access your account history and transactions from anywhere. This is the quickest way to check and see if a transaction has cleared your account.
You can also find out the amount of a transaction after you have lost your receipt. It also allows you to find out about unauthorized transactions more quickly, helping you resolve any issues right away.
Some banks will show you pending transactions. These are transactions that you made that day. If you spot something you did not authorize, you can contact your bank and the vendor in order to reverse the charges.
The sooner you catch a problem like this, the more quickly you can resolve it. Pending transactions may not be for the exact amount of the purchase. For example, if you leave a tip, this will not show on the pending transaction, so keep that in mind as you balance your account.