String literal. A string literal or anonymous string is a type of literal in programming for the representation of a string value within the source code of a computer program.
As usual, the devil is in the details. For instance, with some prepaid wireless plans, your minutes are only good for a limited time, usually 30 to 90 days. If you don't use them before they expire, they are simply subtracted from your account anyway.
A prepaid phone card is used to purchase minutes for a dedicated prepaid phone and phone number. Prepaid phones are a way to avoid signing lengthy cellular service contracts, as those who purchase prepaid phones buy them for a flat fee, then buy the minutes separately and as they go.