What is espresso? It is a brewing method that is know to produce a very strong brew of coffee, with 4x the amount of caffeine. The brewing method involves a machine that utilizes finely grounded [dark roast] coffee beans that are forced through with pressurized steam. The end result is a syrupy like consistency of emulsified coffee particles.
However, a pricey machine is not necessarily the only way to have espresso like coffee. Espresso is valued for its high caffeine content and unique flavor; its strength makes it ideal for use in certain desserts (like with icecream) and even cocktails, such as a White Russian. There are many different methods to produce espresso like coffee. The drip coffee maker is the easiest; you simply add 4x the recommended amount of coffee.
Other methods bring you closer to a true espresso, such as with an AeroPress, A Moka pot, or a French press. All of these use nearly boiling water and finely grounded coffee beans. The AeroPress is the most ideal, as it uses pressure just like an espresso machine would. I’d recommend you check this article out to best use those methods.