Jennifer Gammell has not sat out Black Friday for 19 years — not when she was traveling over the holiday weekend, or living paycheck to paycheck as a young single mother, or even when some of the bargains online began to look more enticing than the doorbuster deals being offered in stores.

The experience has changed over the years. Early on, it was just her and her son Kyle, now 23, waiting in line for discounts (and, sometimes, free toy penguins) at the local Mervyn’s. Now, it has become a family tradition, and her three other sons and her husband, Dave Gammell, sometimes tag along.

The holiday weekend is the busiest shopping period of the year, with an estimated 164 million people — 69 percent of Americans — expected to hunt for deals, according to the National Retail Federation trade group.