The phrase "half-a-bob" is an informal British term used to describe a small amount of money. It is sometimes used jokingly to suggest that someone is cheap or unwilling to spend much. However, there are many other words and phrases that could be used instead. Some synonyms for "half-a-bob" might include "a pittance," "a paltry sum," "a mere trifle," "a token amount," "a smidgen," "a bit of change," "a tiny fraction," or "a modicum." Each of these alternatives conveys a slightly different nuance, but all suggest a small or insignificant amount of money.