I'm certain that MAOI's would potentiate it, however, that combination is extremely risky, and is AFAIK entirely unexplored. I would strongly council against it, and recommend instead simply accepting the ridiculous cost and taking a larger dose, or tripping off of a cheaper drug. PEAs and MAOI's do not get along well (unlike trypts and MAOIs, which is somewhat less dangerous). Also, doing this with cactus extract, instead of pure mescaline, would be significantly more dangerous, because there are all those other alkaloids in the cacti, and it's quite possible that one could be inactive without an MAOI, but be active and toxic when MAO isn't around to shred it as soon as you eat it.
Piracetam would probably potentiate it, but as we know, it's quite unpredictable.
In all cases, the extent of careful experiments needed to ensure safety (slowly working up the dose in combination with the potentiator) would make this a large undertaking. I'd start with no more than 50mg of mescaline and a small dose of the potentiator (maybe 100mg if i was going to use piracetam), and go cautiously from there, if I was to do this, which I wouldnt. The amount of material required for such tests would offset the likely savings in mescaline from potentiating it.
Piracetam would probably potentiate it, but as we know, it's quite unpredictable.
In all cases, the extent of careful experiments needed to ensure safety (slowly working up the dose in combination with the potentiator) would make this a large undertaking. I'd start with no more than 50mg of mescaline and a small dose of the potentiator (maybe 100mg if i was going to use piracetam), and go cautiously from there, if I was to do this, which I wouldnt. The amount of material required for such tests would offset the likely savings in mescaline from potentiating it.