This Town card - a new subtype introduced in this Magic: The Gathering set - is a utility land with two interesting abilities
In support of The Lord of the Rings: Tales of Middle-earth prerelease, youll receive Tarmogoyf (printed in Japanese), Glen Elendra Archmage, Acidic Slime, and Terastodon
If a creature powers up the same turn it enters the battlefield, the activation cost is reduced by that creature's mana value
Like most Magic: The Gathering cards, the value of Doubling Season depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Wilds of Eldraine: Enchanting Tales)
Black Lotus is obviously decent too as are all the stupid blue things (Ancestral Recall and Time Walk)
I remember looking at vanilla creatures that weren't particularly good deals, required obscene amounts of colored mana, and had names that seemed like they'd been crafted by pulling scrabble letters out of a bag blindfolded and thinking this was one of the best things I'd ever seen