Action Points (APs) are a mechanic for helping to save your butt or to let you do a little something extra. You get APs each time you level up, equal to your new level plus your Charisma modifier (minimum of 1, even if you have a CHA penalty). Any leftover APs from your previous level are lost. Most NPCs do not get action points. Normally, spending an AP is a free action you can do once per round on your turn; however, the ones marked with a * are immediate actions you can do as often as desired. What you can do and AP cost is as follows:
BOOST YOUR ROLLS
*Add a bonus to any d20 roll (1 AP): Add 1d6 to any d20 roll, after the roll is made but before you know if success is determined. At 8th level you can roll two dice and choose the better result; at 15 th level three dice; at epic levels four dice.
*Reroll any die roll (except attacks and saves) (2 AP)
*Reroll an attack roll or saving throw (3 AP)
*Automatic natural 20 (except attacks or saves) (4 AP)
*Automatic natural 20 (attack or saving throw) (6 AP)
TAKE EXTRA ACTIONS
-Take an extra move action (2 AP)
-Take an extra standard action (4 AP)
-Duck and cover (variable): Add a dodge bonus to AC of +2 per AP spent. Lasts 1 round.
-Flurry of attacks (1 AP): When making a full attack, take one extra attack at your best BAB.
-Enhance spell power (variable): Increase caster level and save DC of a spell you cast by 1 per AP spent.
-Retain spell (variable): You can cast a spell without losing it from memory or using a spell slot. The AP cost is 1/2 the spell's level (rounding up).
-Spontaneous metamagic (variable): You can add the effect of metamagic feats you know to a spell without affecting its casting spell, spell level, etc. Cost is 1 AP per level adjustment. The adjusted spell level cannot be higher than the highest-level spell you can cast.
-Swap spell (2 AP): You can exchange a prepared spell for any other spell you know of the same level or lower. You can apply metamagic feats you know to a spell you convert in this way, but this extends the casting time to a full-round action.
SAVING YOUR HIDE:
*Ignore condition (2 AP): Ignore a temporary 'condition' (e.g., blinded, confused, dazed, paralyzed, panicked, nauseated, dying) for one round. You can ignore multiple conditions by spending AP for each one you ignore. The duration of the effect continues to elapse while you ignore it. Note that damage (including ability damage, negative levels, etc.) is not a condition and cannot be ignored.
*Delay doom (4 AP): Delay the onset of a permanent 'condition' (e.g., death, petrification, feeblemind, insanity) for one round. You can ignore death even if it is simply from accumulation of damage. If the permanent condition can be negated or countered (using whatever means are normally required to fix the condition, which in the case of accumulated damage just means cure spells) while you are ignoring it, you can avoid it entirely.
You can "overspend" when you run out of APs - if you only have 1 AP left, you can still get an extra standard action or declare a natural 20 or whatever. This doesn't cause a deficit for your next level; it just represents your last gasp of heroic awesomeness. This cannot be done with 0 AP.