If you are new and is looking to rent or purchase card, i would like ARMORSMITH.
Why?
Here's my thoughts,
#1 Repair skill - Restores some armor to the friendly Monster whose armor has taken the most damage
Why issit important you ask? It's because similar to healing, repair allow you to have an edge in the battle.
#2 Only Lvl 1 COMMON REPAIR MONSTER. (refer to https://www.splintercards.com/abilities.php?ab=24)
#3 Cheap rental price - Got mine abit lower, but as of 8 Nov 21 it's around 0.4 DEC.
#4 It's a 0.4 DEC PROMO rental card!!! FYI, PROMO cards give 10% more DEC.
#5 Still a decent price to buy (price trend - https://www.splintercards.com/promo-armorsmith)
Life deck is well known for the double healers, but when paired with ARMORSMITH, the outcome may changed.
Example of a somehow similar match up with and without ARMORSMITH.
(Video link: https://splinterlands.com?p=battle&id=sl_26031efb5687ab7071104b99029f0ed8&ref=mambateddy)