In many cases a market order will fit the bill perfectly. If the price of the stock is near where you’d like it, the stock is not too volatile or illiquid, and you know you definitely want to buy the stock a market order is just perfect for your needs. A limit order is good if you think a stock is overvalued now, but worth buying at a lower price. In that case you could place a limit order below the current price and wait for price to pull back and fill your order. The downside is that price might not ever pull back to fill your order.