Game on. It’s the biggest retail week of the year—the National Retail Federation estimates 147 million people will shop this weekend, either in stores or online. Here's what you should know before shopping. Black all week: Both big box stores and boutiques are starting early. In the Twin Cities, Covered in Uptown will kick off the festivities with 25 percent off from 6 to 8 p.m. Tuesday. OPM and martinpatrick3 are also among the boutiques running pre-Thanksgiving sales. Get the details. Big box hours: Wal-Mart, Sears, and Toys ‘R Us are among the big box stores opening at 8 p.m. on Thursday; Target will follow at 9 p.m. But you can shop many of their Black Friday deals online all week. Mall madness: Mall of America, Southdale Center, Maplewood Mall and Burnsville Center will all be open at midnight on Black Friday—not every store, but many. MOA is expecting 200,000 visitors on Black Friday, so carpool if you can. Do your research: Don’t get caught unprepared. Most retailers have already posted their Black Friday deals online. My first choice is to get the scoop straight from the retailers, but you can also consult one of the more popular Black Friday sites, like BlackFriday.com. Compare prices in advance to make sure the deal is really a deal—especially as the hype increases each year, study after study shows that Black Friday prices are not the lowest of the year. Also remember that many retailers are releasing specials in waves, so schedule your shopping accordingly. There’s an app for that: Verizon clued me in to the Black Friday Survival Guide smartphone app to keep up with sales. In the stores, use Shop Savvy or Red Laser to compare prices on the spot. Shop local: Black Friday isn’t just for chain stores any more. Many independent boutiques are hosting sales and events on Black Friday and Small Business Saturday. Get the highlights here. Don't worry, shop later: This is just the beginning of the holiday sales. Special offers will continue straight through December, and often, they get better the closer we get to Christmas because retailers don't want to get stuck with excess merchandise after the holiday.