The cost of a Christmas tree can vary depending on the size, quality, and where you purchase it from. Generally, smaller trees cost less than larger ones, and artificial trees are often less expensive than real trees. Costco typically has a wide selection of Christmas trees, and the price can range from $20 to $100, with some of the larger and more premium trees costing upwards of $200. It's best to check with your local Costco store or visit their website to see what options are available and the corresponding prices.