How am I supposed to unlock the tile in the Research tab? It doesn't seem to show the price for it.
Ah! That should be explained better. So, when you have Research unlocked. You can move a tile into the slot in the research tab, and hit research. If you don't have that letter already unlocked, it will delete the letter, and add that letter to your available letters to buy. Essentially, you will need to buy the tile again, but now you can just start at that letter instead, without having to buy a bunch of upgrades.