The decor that sells out is never the decor on sale in December. Buy the structural pieces first.

There are two Christmas decor markets. One is the ornament-and-novelty market, which is discounted heavily on December 26th and worth waiting for. The other is the structural market — trees, collars, lighting — which sells out in early December and is never meaningfully discounted while it is still useful.
Early November is the seam between them. Stock is complete, prices have not moved yet, and nothing you buy is competing with the Black Friday electronics rush for your attention or your budget.
The Deal NestThe retro ceramic tree came back and has not left. It needs no water, no storage tree bag and no floor space, which is why it disappears from shelves well before the real trees do. This is a November purchase or a next-year purchase.
The Deal NestCollars have quietly replaced skirts. A woven one hides the stand, survives a cat, and does not need washing every January. Buy it before the tree, not after, because the sizes that fit common trees go first.
The Deal NestThe splurge on this list, and the honest note that goes with it: app-controlled lights only make sense if you are lighting something you will look at all season. If you are stringing one small tree, a plain warm-white set does the same job for a tenth of this.
The Deal NestA warmer runs holiday scent without an open flame, which matters more in December than any other month, when the house is full of people and the tree is dry.
Hold the line on ornaments and novelty until the 26th — that is genuinely the cheapest decor shopping of the year. Everything structural, buy now. The two halves of the season have completely different price curves and treating them the same is what makes December expensive.