Definition:Microtransactions

Microtransactions (shortened to MT in templates) are in-game purchases made with real-life currency, in exchange for in-game items, benefits, or other elements. Most games like this are free-to-play titles that use microtransactions as their primary source of income. Other games cost money at the outset, or require a subscription to play while still allowing microtransactions.

In essence, in exchange for your money, you get something that paying users don't. The effectiveness of the purchase depends on what game you're playing, and how far the developers are willing to go for cash.

Rationale
Microtransactions are not innately problematic. It's the implementation of them that either make or break a game. Because of the flexibility of them, it isn't succinct to go through every possible system and rate them individually (nobody has time for that). Instead, the star rating is used to determine how far the player's money will go should they decide to spend any.

Because of the nature of this particular star system, you can use whatever stars you see fit for the game - as long as it's accurate!

0 stars
The game does not feature any microtransactons at all. The only payment you'll have to deal with is the subscriber's/retail fee that you pay for to access the game itself. If the developer is exceptionally generous, they might release the entire game for free.

Use on game pages.

1 star
Any possible in-game purchases are for purely cosmetic effects that have no effect on gameplay itself. Games like these tend to have tons of cosmetic items and re-skins of regular in-game items to entice users to cash out.

Use on game pages.

2 stars
In-game content can be accessed earlier through microtransactions, such as items that can be unlocked over time or at least obtained in some other way such as crafting or auctions. Games using this system tend to be an exercise in patience for free users, who often have to wait for new items.

Use on game pages.

3 stars
Paying users can access in-game content that non-paying users would have little opportunity to access directly -from outright exclusive items that can be sold to free users at very large in-game prices, to advancement requirements so obscene that paying real currency seems to be the only option to proceed.

Use on game pages.

4 stars
Paying users can access content that non-paying users would never have access to otherwise. Examples include only giving free users a limited portion of the game world, putting in an unreasonably low level cap, and giving paying users a better, longer, more interesting game by extension.

Use on game pages.

5 stars
Microtransactions are a staple requirement of the game. Through extreme restrictions for free users and a combination of the other four stars (often amplified to max capacity), users are required to pay a lot of money to make any meaningful game progress. Most likely a cash cow disguised as a game.

Use on game pages.