We might as well call it Kindle Fire Friday. Amazon revealed today that its Black Friday sales were through the roof for its Kindle lineup, though, as usual, the company didn’t offer any specific numbers.

Amazon said that sales for its entire Kindle lineup were up four times over last year’s Black Friday amount, with the Kindle Fire tablet leading the way. Additionally, the company announced that the Kindle Fire has been its top-selling product for the past eight weeks.

Of course, the numbers aren’t very surprising since Amazon is offering a slew of cheap Kindle devices this year, not to mention the $200 Kindle Fire. Now the Kindle e-reader family starts at $79 for the most basic model, compared to last year’s $139 entry price. Early estimates suggested that Amazon could sell up to 5 million Kindle Fires this year, but at this point I wouldn’t be surprised if the company surpasses 10 million.

With prices being driven inexorably downward, we can expect the Kindle family’s sales to rise even further over coming years. It won’t be long before Amazon offers a completely free Kindle, at which point no other product can hope to top Amazon’s sales charts.