Zero-Level Characters, Part 4: Clerics
Clerics had to wait for the AD&D Second Edition supplemental rulebook Player’s Options: Spells & Magic for cantrips, there named orisons.
In both editions of AD&D, Cantrip/Orison was a first-level spell. That was the cost for them. A first-level caster got four cantrips for the expenditure of a first-level spell. Thus the three grades of zero-level magic-user granting use of 1, 2, and 3 cantrips per day. This can easily be mirrored for clerics.
