The Spirit Magic entry for the Shaman says:
A shaman can spontaneously cast a limited number of spells per day
beyond those she prepared ahead of time. She has one spell slot per
day of each shaman spell level she can cast, not including orisons.
She can choose these spells from the list of spells granted by her
spirits (see the spirit class feature and the wandering spirit class
feature) at the time she casts them. She can enhance these spells
using any metamagic feat that she knows, using up a higher-level spell
slot as required by the feat and increasing the time to cast the spell
(see Spontaneous Casting and Metamagic Feats).
If I understand correctly, a Shaman can spontaneously cast only once a day for each spell level, and only from one of her spirit spells?
So a Level 3 Shaman with the Spirit of Battle has one level 1 slot that she can use to "spontaneously" cast Enlarge Person only, and one level 2 slot that she can use to "spontaneously" cast Fog Cloud only?
Best Answer
Lower-leveled spells can be cast from the same list
Essentially, the Shaman gains 1 spell slot per level that can be used to cast any spell of that level or lower found on their spirit lists.
A hypothetical Level 3 Shaman could use their 1st-level Spirit Magic spell slot to cast the 1st-level spell granted by their Spirit, and then use the second level spell slot to cast the 1st-level spell or the 2nd-level spell granted by their Spirit.
At 4th level and beyond the Shaman can access the list of one other Spirit, doubling the number of spells to select from when spontaneously casting.