If I reach the limit of the GameINI for my game, what options are available in order to increase that limit, and how much do they cost? In addition, increase a PlayerINI limit has the same cost, or different?
You can find most upgrades on the "upgrades" page of your game. For Game- and PlayerINIs I cannot offer anything beyond what's already there, but if you need larger amounts of BDBs than available (or in bigger sizes), send a mail to firstname.lastname@example.org.
If you have a big game and you require more PlayerINI and GameINI storage, I would recommend maxing out the existing options first with Pixels. After you have maxed that out, if you still need more, you should contact Size43 at email@example.com and he will most likely higher the max amount of storage you can have for you. Or at least, that's how it worked for me.