Budgeting tools work best when you're checking them regularly, so you should have a basic idea of what you bought even if you lost the physical receipt. YNAB o

Budgeting tools work best when you're checking them regularly, so you should have a basic idea of what you bought even if you lost the physical receipt. YNAB offers the ability to split transactions over different categories so categorizing an Amazon purchase is trivial. In the case of physical receipts you can enter them before they are synced from your credit card and YNAB does a great job matching uncleared transactions back with the cleared ones. Paypal purchases always have the merchant attached to them, so you should be able to differentiate them regardless of the budgeting app you use.