Skill scrolls are important for your heroes to obtain additional skills.
Each Standard Scroll is valued at 50 skill points, which is enough to level up a skill to level 2 on most common and uncommon heroes.
Ancient Scrolls are valued at 200 skill points. Like the standard scrolls, these also cost 100 gold each, and one of these can provide a significant boost in your skills early on. They also count as 3 scrolls in the Learned Scholar event.