Scrolls do not use spell points to cast. With Scrolls, the caster is still subject to nonlethal damage from casting from a scroll. The same mental focus is required and thus same strain on the body no matter how a spell was cast.
Wands do not use spell points to use. The person using the wand takes half the damage (rounded down) as if they had cast the spell unaided.
Staffs do not cost spell points to use however the spells and # of times they can be used a day is noted in the description of the staff.Casting spells from a staff requires a spellcasting check of 10 + level of spell cast to avoid damage from casting.
Items such as pearl of power(s) restore a certain amount of spell points. Example: Pearl of Power +1 restores enough spellpoints to cast a level one spell. Upon restoring the points, the item is inert until the next day.