Most games sell extras with a made-up currency: gems, coins, V-Bucks-style points. You pay real money for the currency, then spend the currency on items. That extra step is deliberate, and it is the main reason in-game spending is hard to keep an eye on. If your child plays, or you play yourself, it helps to see how the maths works.
Items usually cost an amount of currency, and currency is sold in a handful of fixed packs. The two rarely line up. If a skin costs 800 gems and the nearest pack holds 1,200, you buy the pack and are left with 400 gems that are too few for anything else. Those leftovers are a nudge to buy another pack, and then another.
Packs also get cheaper per gem as they get bigger. That makes the biggest pack look like the smart choice even when only one small item is wanted. Spending also becomes less real: "800 gems" does not feel like a real amount of money the way a price tag does.
The shop below is invented, but the pattern is the one you will find in real games. Tap items to put them in your basket. The shop works out the cheapest way to buy enough gems and shows what is left over.
Green: gems you spend. Coral: gems stuck in the account.
Pick an item to start.
Try the Battle pass (1,100 gems) on its own. No pack matches, so you buy the 1,200 pack and keep 100 gems you cannot use. Now tap a few more items and watch the leftover gems and the price jump around. Small leftovers like these are why many players end up buying “just a bit more”.
Besides the currency step, a few other patterns are worth knowing. Limited-time items create urgency. Loot boxes and card packs sell a chance of an item rather than the item itself, so the real cost of getting the one you want is unknown in advance. Saved cards make buying one tap. None of this means a game is bad, but it explains why a small habit can add up.
The best protection is boring and set up once, before the first purchase request.
Use the family settings on the platform. Console and phone platforms let a parent manage a child's account. On PlayStation, the family app lets parents set a monthly spending limit for the child's store purchases. On Xbox, the Family Settings app has an Ask to Buy option, which sends the parent a request when a child wants to buy something, and lets you review recent spending. Nintendo has its own Parental Controls app. Options and names change, so check what your platform offers today.
Prefer an allowance to a saved card. Adding a fixed amount of store credit each month gives a child a budget they can learn from, and the card stays out of reach. When the money runs out, it is out.
Require approval or a password for purchases. A pause before paying is often enough to stop an impulse buy.
Talk about currencies. Ask your child to convert gems into real money out loud. "That skin costs about as much as a cinema ticket" lands better than "800 gems".
Check the statement. Once a month, look at the purchase history together. It is easier to spot a pattern than to guess one.
Before you say yes to a game with a shop, check three things: does it sell a currency or the items directly, are there loot boxes or random packs, and can you cap spending where the purchase happens. If the answer to the last one is no, keep a card off the account and use an allowance instead.