Apple retailers frequently discount iPhones, Macs and iPads for Black Friday.
Apple Details 17" MacBook Pro Battery Replacements, Same Day Service at Apple Retail
The battery in your MacBook Pro (17-inch, Early 2009) is a consumable item, which means it will require replacement at the end of its useful life. A replacement battery can be purchased directly from Apple. The price of the replacement battery includes installation of your new battery and environmentally responsible disposal of your depleted battery.If you are fortunate enough to live near an Apple Retail location, Apple says the procedure should be a same-day replacement with appointment. Mail-in replacements, however, will require 3-4 business days after shipment of the unit.
Apple claims that their improved battery technology will allow up to 5 years without needing a replacement.