Whether you're building a game on blockchain or any other kind of dApp, you will probably be selling some digital asset. Maybe an NFT that acts as an in-game item or some fungible token with in-game utility. Whatever it is, you need to price the item appropriately.
A lot of dApps price things in the blockchain's native currency (ETH on Ethereum, KOIN on Koinos, etc.), and that's perfectly fine in certain cases. This approach directly ties the value of your dApp's assets to the value of the blockchain. 10 ETH was probably a reasonable price for something a few years ago, but most people aren't willing to pay that much for new projects now.
If you're building a game, it probably makes the most sense to have an in-game currency that's used to price other in-game assets. This allows you to manage the game's economy more effectively through token creation and burning.
Your game's revenue won't be in the form of in-game currency, though. Most likely, you'll use Stripe or a similar service to charge credit cards, accept the blockchain's native currency, and even stable coin transactions. By providing options, you can serve different segments of users. Blockchain early adopters may prefer the native currency, but "normal people" are more familiar with credit cards.
However you decide to price, think about the implications to your dApp economy, the accessibility for various kinds of users, and whether you will need to regularly adjust pricing based on the market.
P.S. In case you missed it, the Koinos Group released a new unified whitepaper while I was away! Give it a read