If you've fully completed Discordant Studies (and therefore all the Seals), it'll cost exactly one Memory of a Much Lesser Self from the card <a href="/wiki/Again_and_Again" title="Again and Again">Again and Again</a>, making it approx. 2.50E. This is the cheapest it comes, as these memories will be pretty costly to gain from most of the other sources throughout <a href="/wiki/The_Lower_Castle" title="The Lower Castle">Discordant</a> <a href="/wiki/The_Upper_Castle" title="The Upper Castle">Studies</a>.