Black Friday is just right around the corner with just few days left before the said event. But before you go shopping this coming Black Friday, here are some things you need to know.

1.Doorbuster Deals starts before Black Friday

Overstock offered shoppers doorbuster previews as early as October this year. Amazon has released new deals every day in November as part of its countdown to Black Friday week. Dell staggers its doorbusters by the hour. For example, the Inspiron 11 3000 laptop kicks off the online sale at 6 p.m. Eastern time on Thanksgiving, while the Garmin Vivofit activity tracker goes on sale at 3 p.m. on Black Friday. Always try checking retailers' website early for you to avoid missing the item you want.

2.What You See Isn't Always What You Get

At some retailers, items are claimed before the sale officially starts; Best Buy stores typically hand out tickets for in-store deals a couple of hours before the doors open. And on Thanksgiving 2015, Sears sold a Kenmore refrigerator at a 52% discount but carried only about two per store. Just because you spot a spectacular deal in a retailer's Black Friday ad doesn't mean the store will have it.

3.If The Store is Out of Stock, You are not Out of Luck

Walmart's 1-Hour Guarantee lets in-store shoppers buy certain items that sell out within the first hour of the event at Black Friday prices and have them shipped to the store by Christmas. And the Sears Holiday Guarantee promises members of its Shop Your Way rewards program a partial reimbursement on select purchases if the department store sells the same product for less during the holiday season. And stores aren't your only option. Plenty of retailers offer their in-store deals online or have online-only doorbusters.

4.Return Policy Vary

Most retailers accept returns. Some even extend their return policies during the holiday season. However, there may be final sales, exclusions or conditions. Take Target, where the return period for drones, electronics and entertainment items purchased on Black Friday won't start until the day after Christmas.