Most creatures will be aggressive towards you if you have a chaotic alignment
Many merchants refuse to sell to chaotic players, and frequently other NPCs like rangers and guardians will try to kill chaotic players without Knight online Gold provocation.
There are more challenges that you should be aware of if you decide to play a chaotic character. You are more likely to drop items when you die than those of neutral or lawful alignment; you even have a chance of dropping non-quest spells when you die!
(In fact, when you become fully lawful, you will only have a small chance of dropping items at all when killed.)
Most creatures will be aggressive towards you if you have a chaotic alignment. There is, however, an NPC in certain towns that will teleport players of chaotic alignment to the Fire-Field Farmer's Town where you will be able to purchase merchandise.
In addition, any existing lawful player may attack and kill you without any negative alignment effect.
In fact, they receive a positive alignment bonus for bringing chaotic players to justice!
Other elements that affect alignment are spells and pets. Spells have an alignment of neutral, lawful or chaotic that will affect the caster's alignment each time they use the spell.