Cheap
sex is what a person generally gets if they solicit sex in a
bar, from a
prostitute, or in another situation where sex is had with no emotional meaning or bond between parties. The "
cheap" refers not to the price of the prostitute or the drinks at the bar, but to the fact that it is totally devoid of any form of deep meaning.
While humans obviously have strong sex drives and often feel the need to exercise them regularly, many people believe that sex tends to be more rewarding if there is an emotional connection between parties which transcends the performance of the act itself and the lust involved. This isn't to say that all sex should be between people in committed relationships, but there sex tends to be better if there exists some attraction which is more than merely physical.