It's even cheaper at Atlex.com. $1,099 less $300 rebate is $799. And that includes shipping.
Keep in mind that a complete set of ink and a new waste tank is about $425. You're only paying $374 more for the printer.
Now it's time for the fun math. A two year extension on the warranty is $300 and entitles you to a refurbished printer should yours die.
For $75 more, you can have a spare, brand new, printer waiting to use.
The downside, is that buying a spare only covers one failure. The upside is that it covers all failures (even if you drop your original printer) and you don't need to wait for the replacement to arrive. If you never use the spare, you can likely get a few hundred on ebay for an unused 3880 without ink.
If you operate multiple 3880s, having a spare is probably a good idea. The spare printer can replace any of your 3880s that fail. If you prefer the extended warranty, you would need one for each of your printers.