Chris Cheng doesn't need 40 hand warmers right now, but the longtime Amazon.com customer is loading up on them anyway.

With the Internet retail giant set to begin collecting sales taxes on California purchases Sept. 15, the San Francisco resident is among many tech-savvy consumers trying to cram in some last-minute tax-free shopping.

Depending on where they live, Californians pay 7.25% to 9.75% in sales taxes, so the savings are substantial — especially on big-ticket items such as electronics. But bargain hunters are also stocking up on inexpensive goods such as food, DVDs and carpet cleaner.

"I've ordered nine things in the last two weeks," said Cheng, 32, whose purchases include a hands-free roaming camera for $199.99, five pounds of protein powder for $53.99 and exercise resistance bands for $26.99. "Any time you can save money, that's a good thing."