By SARAH SKIDMORE

Associated Press

PORTLAND, Ore. -- Shopping on Black Friday can be daunting, with massive crowds, pre-dawn start times and long checkout lines.

Roughly 77 million Americans are expected to head to stores Friday, the day after Thanksgiving and often considered the start of the holiday shopping season, and the frenzy will continue through the weekend.

But whether it's worth participating depends on who's shopping, what they want and all the costs involved.

Here's what to keep in mind:

* The shopper: This is the biggest factor. Some people love the thrill of the chase. They want to score a deal, and they like the tradition. To them, Black Friday is worth the effort no matter the hassle.

"There is a visceral excitement to going to stores on Black Friday; it's almost like a sporting event," said Dan de Grandpre, editor in chief of online shopping and discount guide dealnews.com.

Even though promotions pervade the season, the ideal Black Friday shopper responds to the sense of urgency and exclusivity that retailers create for that day with early openings and a limited number of items discounted, said Steven Hoch, a marketing professor at the University of Pennsylvania's Wharton business school.

* The item: Retailers count on the excitement of Black Friday to ignite holiday shopping, so they use big, attention-grabbing discounts to lure shoppers. The most notable deals are usually on big-ticket purchases such as televisions, computers and other electronics, de Grandpre said.

There might be more discounts this year on smaller items such as sweatshirts or coffee pots to cater to shoppers' more modest ways. But the big splash is where the big savings lie.

"Those are the things that get people whipped into a frenzy," de Grandpre said.

* The costs: After you determine (ahead of time) what you should pay for the items you want (consumers are comparison-shopping more than they have in years, according to the NPD Group), then decide whether your savings will be worth your additional costs.

Count the value of your time, the gas to get to the store and circle for parking, the extra snacks at the food court and any other costs you incur simply because you are shopping.

Also remember the add-ons: the cable to go with the super-cheap television and the impulse purchases you make while roaming the aisles when they're out of the item you came for. One of the easiest ways to limit those costs is to shop online.