It's time to take everything you learned in college about economies of scale and apply it to that ink-sucking monster with the lonely USB cable. Is it cheaper to print photo-quality prints at home, or through an online vendor? This spreadsheet knows.
It's a helpful, formula-laden, and free download at the How-To Geek's own site, where Eric Z. Goodnight has detailed all the Google searches, cost-per-page figures, and ink yield data you'll need to put together to figure out whether your Canon, HP, Epson, or Lexmark is as effective as a Snapfish, Kodak, or other e-print provider. XLS-formatted spreadsheet download can be found in the middle of the post.
Is Your Desktop Printer More Expensive Than Printing Services? - [How-To Geek]