If you shop online like I do but prefer to keep electronic copies of the "receipts" you're shown once you place an order instead of printing them, I just discovered a cool little feature in OSX you might find handy.
If you want to save that receipt electronically, just go to File>Print... In the print window, click the PDF button in the lower left and scroll down to Save PDF to Web Receipts Folder...
The first time you do this, it creates a Web Receipts folder in your Docs folder, and you can then find all of your e-receipts there henceforth.
CJR, I've been saving web purchase confirmations/receipts as PDRs for quite a while, but had created my own "Purchases" folder -- never noticed the "Web Receipts" option -- thanks! (So much nicer than a pile of printed confirmations/receipts, isn't it?)