The new 17″ MacBook Pro's non-removable battery will cost $179. The swap will take along time says apple spokesperson.
From a spokesperson at Apple:
It will likely be years before you need to replace it (1000 cycles at 200 cycles/year = 5 years). You can have the battery replaced at any Apple Store or Apple-authorized reseller. The replacement battery is priced at $179, which includes installation of the new battery and environmentally-responsible disposal of the old battery.
The non-removable MacBook Air battery costs $129 to replace, though the lifespan is not promised to be as great.
From Apple's website:
The longest-lasting Mac notebook battery ever.
The battery in the new 17-inch MacBook Pro lasts up to 8 hours on a single charge and can be recharged up to 1000 times2 — compared with only 200 to 300 times for typical notebooks.