LOS ANGELES (AP) — Shoppers have been mostly peaceful as thousands lined up in the wee hours today to get discounts of up to 70 percent.

In Los Angeles, though, authorities say 20 people at a Walmart store suffered minor injuries when a woman used pepper spray to keep shoppers away from merchandise she wanted shortly after the store opened. Police are still looking for her.

Some 152 million people are expected to holiday shop today, tomorrow and Sunday.

The onset of Black Friday puts retailers in that pins-and-needles time of year which could determine as much as 40 percent of annual revenue.

It's expected that shoppers will spend nearly $500 billion during the holiday shopping season, or about 3 percent more than they did last year.