What is the Shilling symbol?

If the question is regarding the pre-decimal British coin, the symbol is a lower case "s".

For example, Two Shillings can be expressed as 2s, which is how it may have appeared on a train ticket, a restaurant menu or a theatre ticket.

Alternatively, Two Shillings may have been written as 2/-. The slash is a seperater between the denominations, and the dash represents a value of zero (Pennies in this case).