You do not have to be rich before you can be a market maker. You can either be a market taker or market maker while trading.

Market takers are those that their orders are filled immediately which can be as a result of using market order or buying at a higher price or selling at a lower price.

Market makers are those that their orders are filled not immediately but it can take some seconds or some minutes or days until the the price they set is reached. Market makers use limit order and set the price lower for buying order or set price higher for selling so that the order is not filled immediately but until the price is reached.