This story is part of Gift Guide, our year-round collection of the best gift ideas.

AT&T is giving away Samsung's Galaxy S21 this Cyber Monday as long as you meet the carrier's conditions. The Galaxy S21 is Samsung's flagship smartphone from 2021 that comes with 6.2-inch screen and a triple-lens camera.

To take advantage of the deal, you'll need to buy the Galaxy S21 through AT&T's monthly installment payment plan instead of buying the device outright. You'll also have to pay taxes on the full retail amount up front and pay the $30 activation or upgrade fee. The deal is only available for those who activate or continue paying for AT&T's unlimited wireless service plan.

If you meet those requirements, you'll get up to $800 in bill credits toward your Samsung Galaxy S21. It's important to note that these credits only start after three bills, but AT&T says you'll receive catch-up credits later. If you cancel your service, the credits will stop and you'll be responsible for the remaining balance.

The deal is only valid on Nov. 29. Although there are several conditions in the fine print, it's still a good deal for those who are planning to stick with AT&T for the longterm or are considering switching to its service. Many deals like this usually require you to trade in your old device to get such a big discount, so this deal is notable for that reason as well.

The Galaxy S21 is almost a year old, which means it's likely almost time for the Galaxy S22. But the Galaxy S21 is still an excellent choice for those who want a compact, well-designed Android phone with a solid camera, smooth screen and decent battery life.