another stupid question

where do i get runes and how rare are they?

Runes are rare and have to be salvaged from an appropriate rare item using an Expert Salvage Kit. Here's a few examples:

Monk Rune: Axe Fiend Armor, Centaur Vest, Flame Wielder Trappings
Necromancer Rune: Blighter's Togs, Decayed Orr Robes
Mesmer Rune: Dwarven Scout Armor
Elementalist Rune: Ghoul's Collar, Shaman Garb
Warrior Rune: Rare Flame Wielder Trappings

You can get runes by salvaging any armor that drops- they're listed as "Salvage Items" when they are in your inventory. You're more likely to get a rune from a rare armor, though you can get runes from any of them. You just need to salvage using an Expert Salvage Kit. As far as I've been able to tell, there's no correlation between the type of armor you salvage and the type of rune you'll get from salvaging it. However, high-level armors are more likely to yield Major and Superior runes than low-level armors, so if you're looking for those runes, you should try to get armors from later missions such as Riverside Province. If you're just hunting for minor runes, you can generally do well by killing Charr in the early missions such as Fort Ranik.