Armor is a trade-off between protection and mobility.
Soft Armor such as soft leather, padded tunics, or the heavy robes favored by magic-users.
AC 11 for 10 silver. Counts as a heavy item, but does not hinder movement otherwise (120''turn, 40'/round.
Light Armor such as boiled leather plates, gladiator harness, or layered hides & furs.
AC 13 for 20 silver. Slows movement to 90'/turn & 30'/round.
Medium Armor such as chainmail or basic plate (breastplate, greaves & bracers).
AC 15 for 40 silver (plate) or 60 silver (chain). Slows movement to 60'/turn & 20'/round.
Heavy Armor layers plate & chain for maximum protection.
AC 17 for 100 silver. Slows movement to 60'/turn & 20'/round and counts as a heavy item.
Shields are wooden with metal reinforcements and may be painted with a design indicative of the bearer or his company or lord. Special: When the bearer would be reduced to 0 hp, the shield is destroyed and the bearer reduced to 1 hp instead.
AC 12, or +1 to other armor, for 30 silver. Counts as a heavy item.
In the Dark Age of Partholon, chainmail is the pinnacle of military technology. A smith who can craft mail is rare indeed, so most warriors get by with basic plate. A fighter in plate & chain might as well be Robocop as far as the peasantry is concerned, and anyone traveling in such harness will generate ripples of gossip.
Soft armors can generally pass for civilian garb and do not mark the wearer as a combatant. A padded tunic may be the outfit of choice for a career warrior whenever heavier armor would be socially unacceptable.
[Edited to reflect updates in my campaign.]