If you are a parent, renting a game is sometimes a better option then buying. In this day and age there are some games that are not appropriate for young children. Every game has an ESRB rating (Entertainment Software Rating Board) that gives you an idea of what type of content you can expect in the game, but it does not go into full detail. Most of the ratings say mild sexual themes, partial nudity, violence, bad language, mild suggestive themes, ect... but it never says to what extent. You could purchase a game that says violence but is that just shooting or is it chopping up body parts? There's no real way to tell, until you actually play the game yourself. By renting a video game you can see all the game has to offer without spending a ton of money. If the game turns out to be unsuitable for your child, return it and you can choose another title.
I work part time in a video game store, for personal reasons I won't say which one. On more then one occasion parents have asked me for advice on video games. Last week I had a mother ask me if a certain title was suitable for her son, who was ten. The game was rated mature for sexual themes and violence. I hadn't had a chance to play that specific title and couldn't give her my honest opinion of it. Of course her son went on to say how his friend had the game and it wasn't that violent and she should just buy it. Her situation was a bit different because if the game was not appropriate her husband would have a fit. She debated on whether or not to buy the game. Since he was so young I advised her not to buy the game, because once you open it you can't return it. I watched her think it over in her head for a few minutes, before finally breaking down and purchasing the game.
I had the liberty of testing out that same game a week later and it was definitely rated mature for a reason. I've watched parents buy their young kids Grand Theft Auto, a game where you go around shooting, killing and stealing cars. When I tell the parents that the game is rated M for mature, they buy it anyway. It may be some parents are clueless as to what rated M actually means. If you look up what all the ESRB ratings stand for, you'll learn that M is for teens 17 yrs old and up.
If you are a parent who is concerned about what your child is being exposed to I recommend renting over buying. This way you don't spend a ton of money on a game you decided is not age appropriate.