What ways are there to either reduce power point costs or increase the effective manifester level for a psionic power—apart from Overcharge, the wilder class in general, or the torc of power preservation—, so that the power is augmented beyond the usual limits set by your manifester level? Even if the method works for a single power, or a single manifestation, it is still useful.
This Psionic PrC is the simple answer to more manifesting. It doesn't break the limits in an extraordinary way, but it does several useful things:
1) It grants more power points, which is essentially reduced costs aka more manifesting per day.
2) The capstone quite simply says that once per day for 1 minute you gain some defenses and infinite manifesting. Doesn't say he can actually exceed his manifester level, but zero cost powers for the duration of several encounters is really legit
Access: Level 6 to get into the class, level 16 for the capstone.
This is an out-of-the-way base class from Dreamscarred Press (same people who did Psionics for Pathfinder). Akashic magic is totally legit, and this class is 10x more awesome than it seems on the first read. I could rave about it, but I'll cut short the rave with telling anyone who reads this to play this class through level 1-20 just once, and you'll realize how fantastic it I (no...seriously. Do. It.). ANYHOW, the key part you care about is thus:
1) dipping into the class, just 1 level will suffice. The class also has other synergies with just about any class that make it surprisingly useful, even at level 1. A 3 level dip would be worth it, IMO, but 1 level is all you need.
2) Taking the Akashic Augmentation feat. This allows you to invest some of your essence (kinda like power points for Akashic magic) into the feat, reducing the power point cost of a select power. Limited, but nifty.
Access: Dip, so whenever.
This Psionics PrC is your best bet. Dip into an arcane casting class, and then take this dual-progression class. It progresses your casting, meaning you end up getting spells from that dip (useful) but the key part is that you can sacrifice spell slots to boost powers for free. When you are talking things like 9th level spell slots you’re sacrificing, that is a huge augmentation and boost to the DCs. How this interacts with manifester level isn’t clear, but ostensibly it bypasses the limitations since you aren’t actually augmenting the powers. Even if it doesn’t, though, you’re dropping the cost ridiculously. Excellent choice for any super-high-powered psionics manifester build. #1 choice right here.
Access: PrC, whenever you can get ahold of 2nd level arcane spells. I would recommend going after the most spells per day you can.