When a person purchases something for very little money or for less than he thought he would have to spend, he may tell others about his good fortune by saying he got it for a song. This basically just means that he purchased it cheaply. The phrase is an idiom, or figurative expression, that is commonly used in some places. Usually, however, it is used in casual speech and in situations in which friendly, figurative speech is considered acceptable. A person is, for example, more likely to use an idiom when speaking to friends than he is when speaking to an interviewer while applying for a job.
Many people are thrilled when they are able to purchase something cheaply. For example, an individual may appreciate a new pair a shoes if he likes the style, but he may be even more appreciative if he can buy a pair of shoes he likes for a lower-than-normal price. When a person purchases something for cheaper than normal, he may say that he purchased it for song. This is basically just an interesting, figurative way of saying he got it cheaply.
It is important to note that a person is unlikely to understand what “for a song” means if he is not from a region in which the phrase is commonly used. Idioms tend to be specific to particular regions. As such, a person who lives in one region may be familiar with most, if not all, of the idioms that are commonly used there but not understand any of those used in other regions. For this reason, idioms sometimes must be defined or explained for travelers or those from outside the area.
There are many examples a person can consider when he is trying to understand what “for a song” means. One example could involve a person who has been complemented on a sleek sports car he has recently purchased. The new owner may be pleased that the person is admiring his car and want to share the low price for which he was able to purchase it. In such a case, he may say that he bought the car for a song rather than simply stating that he purchased it cheaply. To some people, the use of the idiom may make the conversation seem more interesting or colorful.