Do they sell out every year before you remember to think of them? Not this year—right now Amazon has the 2018 LEGO City Advent Calendar in stock and priced at just under $22. If you prefer the LEGO Friends version, that’s $25, and the LEGO Star Wars version is in stock (good) but still at full retail of $40 (not so good). But you do you.
No matter which one you choose, I promise you won’t be able to find them in December. Plan early and make ’em happy, folks. (I say this as someone who purchased Advent calendars for her teens for quite a while….)