There is quite a selection of golf bags on the market: some are very pretty, designer bags, made for looking good; others are practical golf bags designed by golfers for golfers and some are half-way between the two types. Then there is 'big', 'bigger' and 'ginormous' - big enough to use as a suitcase.
As a rule of thumb, you only need a golf bag large enough to hold your clubs, spare balls, your glove,...