You can ignore any transaction by tapping on it and taping the "Ignore" row. There are two options:
Ignore from Budgets - This will keep the transaction in your spending report but will ignore it from your budgeted spending. This is useful when you have a large ticket item you have saved up for (like purchasing a car or vacation). In such a case, you often don't want it to blow out your monthly budget, but still want to track the fact that you spent that money.
Ignore from Everything - This will ignore the transaction from all budget, spending and other reports. The transaction will still show up in your Transactions tab.