Amazon Prime Big Deal Days will begin Oct. 6 at 12:01 a.m. PDT and run until 11:59 p.m. PDT on Oct. 7. That's two full days of deals for Amazon's annual fall sale.Before the sale starts, we want to ensure you're set to score the best prices. First and foremost, you must be a Prime member to receive discounts on select items.Right now, you can sign up for a free 30-day trial of Prime. After that, an annual Prime membership costs $139 per year or …