I also found this to be the case. I found that the cost of letters is always increasing.
I thought upgrading Ink Economy was supposed to decrease the cost?
I'm not noticing any decrease. Maybe I'm doing it wrong?
I'm enjoying the game though.
Thank you very much for playing. Yes cost of letter increase as you go but resets if you prestige (aka publish new edition). Intend was to move away from monotonous word searches and force player to upgrade and prestige. I'll update ui.