“There is a best time to buy notebooks, and it is exactly when you think it is, between the last week in July and the first three weeks in August, when the back-to-school merchandising frenzy is in full force,” said Analyst Stephen Baker, who studies laptop pricing and sales for the NPD Group, a market intelligence firm. He noted that this time frame applies to both Macs and PCs.
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Bottom Line: You’ll find more deals in the July/August and November/December time frames and will see new model releases in early spring, midsummer and fall.

Source: The Best Time to Buy a Laptop