If you’re looking to buy an espresso machine, the first thing you need to figure out is what type of espresso machine best suits you.
Types of espresso machines

Mechanically, there are two basic types of espresso machines: steam-driven and pump-driven. Steam-driven machines The very first espresso machines worked on a steam-pressure basis, and they’re still in use today. With this type of machine, steam or steam pressure is used to force water through the coffee grounds and produce espresso. Some steam-driven machines can produce a measure of foam “crema.” But they can’t generate enough pressure or provide the precise temperature control necessary to produce true espresso: They simply make a very strong cup of coffee. However, they cost considerably less than pump-driven machines. Our verdict is that if you’re a true espresso lover and seeking to make a good shot at home, we recommend you steer clear of steam-driven machines. They’ll likely disappoint you.
 Tip: While we don’t recommend steam-driven units, If you’re on an extremely tight budget and looking to “test the waters” with a low-cost, entry-level machine, a steam-driven model will provide a somewhat cheap imitation of espresso. (Source)