You make a sacrifice to aid in conjuring and commanding a creature called with planar ally, planar binding, or a similar spell. A sacrifice can be used in a variety of ways:

A sacrifice may consist of any kind of commodity the target creature favors, including treasures, living creatures, or more ephemeral offerings. While this spell is not fundamentally evil, good-aligned creatures prove more selective in what offerings they accept, typically scoffing at blood sacrifices. Many sacrifices are fundamentally evil acts, such as murdering a pious innocent to summon a fiend. Any creature might reject certain types of sacrifices, thus denying you the benefits of this spell, as the offering must appeal to the target—few outsiders would care for 2,000 gp worth of parchment, while 2,000 gp of diamonds would be widely coveted. The GM determines what sacrifices creatures find appealing.

The Sacrifice Effects Table lists a number of likely offerings, along with the bonus such gifts effect and the offering’s equivalent value in gold pieces for the purposes of planar ally. Several of these sacrifices involve the loss of ability scores, levels, lives, or even changes in alignment. Any change wrought by such sacrifices (loss of ability score or level, or change in alignment) cannot be recovered, cured, or undone by any spell or effect short of miracle or wish. The same is true of creatures killed as a sacrifice; such creatures cannot be resurrected by any magic less powerful than these spells. Any object sacrificed with this spell is effectively destroyed or removed to an extraplanar holding of the summoned creature’s choice. The bonuses and values noted on the sacrifices table are guidelines for offerings; certain types of treasures or lives might prove especially valuable to specific creatures, with extraordinary sacrifices (like a potent artifact or the life of a high-level paladin) garnering increased bonuses.

You cannot make greater sacrifices than those noted on the table to gain increased bonuses or gold values. For example, you could not gain two permanent negative levels to gain a +16 bonus nor gain increased benefit from slaying 20 HD worth of creatures to pay for a 10 HD creature’s service.