You can buy COPYABLE SCROLLS and ONE-USE ONLY SCROLLS in some locations. One-use scrolls are helpful for PvP, they are the brown and "cheap" ones, the blue expensives being the copyable scrolls.

Here is the list of the ONE-USE SCROLLS that you can find in Athas, with their prices.

At Ibod, in Caravan Way:

Level 1 (450 CPs):

• Armor
• Enlarge

At Naamo, in Elven Caravan:

Level 1 (450 CPs):

• Armor
• Magic Missile

At Daaku, in Elven Caravan:

Level 3 (750-900 CPs):

• Blink
• Dispel Magic
• Haste
• Lightning Bolt
• Vampiric Touch

Level 4 (937-1125 CPs):

• Charm Monster
• Minor Globe of Invulnerability (2250-2700 CPs!)

Level 5 (1125-1350 CPs):

• Cone of Cold

Level 6 (1312-1575 CPs):

• Chain Lightning
• Disintegrate

Level 7 (1500-1800 CPs):

• Conjure Greater Elemental
• Control Undead
• Forcecage

Level 8 (1687-2025 CPs):

• Incendiary Cloud
• Mind Blank
• Monster Summoning VI
• Spell Immunity

Note:

Meteor Swarm scroll can't be bought anymore, but it can be found as treasure in certain places.
Otto's Irresistible Dance scroll can't be bought anymore, and I'm not sure it can be found as treasure .

Tip:

To know what you're buying, right-clic on the scroll to have info, then right-clic again on the icon to have a clear description of the spell.