Luckily, it isn't very common to see games in which a player can use real money to buy an immediate advantage in the game. I understand that in some games, DLC can ultimately result in the player gaining an advantage (for example, Borderlands 2 DLC offers more weapons, items, and levels). However, the player must also work in the game for the advantages in most cases.

It was never unheard of for players to be able to use their mom's credit card to get extra lives (or whatever is offered), but GTA V is a popular game, so this is a popular example.

The cash cards are not available yet, but they obviously will be (or are planned to be at the moment). I was told that $12 was about 1 or 2 million dollars (this could be completely wrong, this is a fact from a friend I was talking to, but the exact prices don't matter). What is Rockstar thinking? Money in GTA V online is extremely essential. This isn't an add-on such as camo in BO2 that simply gives an edge in appearance. This is an advantage that is only second to the advantage of level.

I think any and all games should simply depend on skill, time played(unlocks, practice), and possibly some other aspects, but not real money.

In basic terms, I see some immediate problems with this:
1. A player can spend about $30, and buy a tank for his/her hangar.
2. On the contrary, a player without as much real money can spend hours in-game and have a bike to show for it.
3. The game could easily be based on real money, not other aspects.
4. When glitches to obtain money are found out, that means people are gaining millions through a glitch while others are paying real money for it. This is a problem for obvious reasons.