Not all Artifact cards are born equal: the worst cards are almost worthless—although you can at the very least recycle 20 of them into an event ticket—whereas the best cards are in high demand on the Steam market and cost multiple dollars each.
It is important to note that rarity and power are not tightly connected in Artifact. There are excellent common cards, such as Bronze Legionnaire, that can be bought for mere $0.03 on the Steam market, because players who open a lot of packs have tens of them. Even staple uncommon cards are relatively inexpensive. For example, Legion Commander, a red hero who is played in practically all red decks, currently costs $0.52 on the market.
Nonetheless, to unleash the full power of your deck, you also need some rare cards. Not all rare cards are good, but the highest priced of them are—they wouldn't be so valuable if they weren't getting play.
Note that the market prices are constantly changing: the prices cited here are a snapshot of the market at one point in time. The overall market prices change, and as the meta develops and cards find new uses in meta decks or fall out of favor, the prices of individual cards compared to others change as well.
For tips on how to play Artifact, head to our Artifact guide.
Honorable mention: Blink Dagger ($1.73)
Blink Dagger is the most powerful item in the game: you can move the hero wielding it to another lane every other turn, and this mobility makes it easy to respond to threats or exploit weaknesses. It is used in three copies in the majority of constructed decks regardless of colors. Accordingly, Blink Dagger is by far the most expensive uncommon card in the game.
Cheating Death ($2.44)
Cheating Death is quickly rising up as the most annoying card in the game to play against. When you have a green hero in the lane, all of your units have 50% chance to survive lethal damage. We have already had the pleasure to witness Cheating Death vs Cheating Death lanes in tournaments, where things just die or survive at random.
At Any Cost ($2.95)
At Any Cost is the weaker and cheaper—both in terms of mana and dollars—of the blue board clear spells. While it currently sees less play than its big brother Annihilation, it is a key anti-aggro card and something to bring in whenever aggro gives you a hard time.
Unearthed Secrets ($3.12)
Unearthed Secrets is a Green improvement that can be stuck on your weakest lane for extra card draw. It's seeing a good amount of play in Green/Red decks.
Tinker ($4.57)
Tinker is a black hero that zaps down enemy units and comes with a strong signature card, March of the Machines, which is an improvement that deals damage to the enemy tower and each enemy in the lane over multiple turns. Tinker is a popular hero in Red/Black aggro decks that are some of the top decks right now.
Emissary of the Quorum ($4.65)
Emissary of the Quorum is a Green creep that is popular in ramp and combo decks. Its active ability permanently buffs all of your units in the lane and can be used every turn, which means that it can rapidly snowball out of control if not answered immediately. It costs eight mana, so one way to counter it is to win the game before it can hit the board.
Horn of the Alpha ($4.00)
Horn of the Alpha is used in decks that are able to amass a lot of gold quickly. It costs 25 gold from the shop, so getting one to your hero is no easy task, but it allows the hero to summon a powerful Thunderhide Pack (14/14, siege 6) every other turn, putting immense pressure on the opposing tower.
Time of Triumph ($8.02)
Time of Triumph is the ultimate red finisher. Essentially, it turns all your heroes in the lane into superheroes—permanently. If it does not win the game on the spot, those heroes will be incredibly difficult to deal with in the upcoming turns as well.
Annihilation ($8.38)
Annihilation is the supreme blue board clear. Condemn all units. Everything. Wipe the entire lane with one big bang. That’s power.
Kanna ($8.89)
At 12 health, Kanna is the sturdiest blue hero in the game. Blue as a color has some great spells and needs its heroes to survive to cast them, and Kanna fits the bill perfectly. Her signature card, Prey on the Weak, can summon a large board when there are multiple damaged units in the lane, and making that happen with blue is a walk in the park.
Drow Ranger ($13.57)
Drow Ranger’s passive effect provides more attack for all of your units in all lanes and her signature card, Gust, prevents the opponent from casting spells in the lane for a turn, which simply wins games. Accordingly, it is difficult, if not impossible, to find a green deck without Drow Ranger.
Axe ($17.91)
Red heroes are typically big and tough, and Axe is no exception. Unlike many of the others, he also has two armor, which makes him impervious to regular creeps. Furthermore, whereas most red heroes have weak signature cards, Axe has Berserker’s Call, which allows a big hero to wipe out nearby enemies and clear the path to hit the tower.