SPOILERS - Special trade

[Caïn]

I just found my first sanctum key in Room 46 . When i go the Trading Post , I have the opportunity to trade it for an Allowance Token .

Will I be able to get another Sanctum key ? Or is it lost forever ?
Also, i already found several Allowance Tokens . Is there any purpose to collect them all ? And if so, should i do this trade ?

[Forblaze]

I have no idea what happens if you make that trade

Allowance is functionally infinite. Some showroom items can be traded infinitely for allowance tokens and one of the experiment results also increases your allowance.

They're not really something that needs hunted but you'll find them when you do other puzzles.

[SamuraiJones]

Sanctum keys are scripted. There are a certain number per save file and no way to get more. You will need them all for some post-game stuff.

It'd clearly be a bug if it was possible to destroy something necessary... but i'm not sure i'd be willing to take that risk.

edit: Sorry, missed your second question... are forblaze said, allowance tokens are rare, but not finite. I don't think you could ever "get them all" any more than you could get all the gems.

[Doombringer]

Cloister of Lydia and Quest Bedroom and Trading Post with high cost items from the showroom and lab experiments are all uncapped sources of +allowance.
Use the sigil key, don't trade it...

[pressea]

Although I haven't traded it, I am 99% sure that it will spawn again where you found it. This happens with a lot of items, and it even happened to the very first one I got that I lost to an effect like 5 steps after getting it, lol. So, if you really wanted to, you could use it as a repeatable source of allowance. If it's an easy one to reach, I'd even say I recommend it since it's not very useful without other info.

[jokeserver]

I lost one from a particular room by coming up two steps short of the Sanctum... I would be really sad if my dumb errors to go a few steps in the wrong direction/needing to backtrack for food I should have gotten results in an uncompletable save file.

In another similar thread while searching for this info, someone mentioned finding a new key in one of their other places, so maybe I will be lucky later. But for now it feels very bad.

Edit: Library records how many I've "found" but it's actually the number of doors unlocked, so... maybe it'll correct itself after all?

[Vardis]

Huh, I was only offered a Prism key. Apparently I need to work on my bartering skill. :p

[jokeserver]

That particular room has given me a new key, on something like the fourth subsequent time that I met the conditions for it to do so. So it can happen.