The first thing to do is your homework. You will need to figure out what type of machine you need. Ask your self how many cups of cappuccino or espresso do you drink a week? Where do you normally have it? At home or from a coffee bar. After you have decided what your needs are then it's time to shop.
You can purchase a single cup serving machine or multiple. Plastic, stainless steal, copper, the lists go on as to what is available. The prices range from a couple hundred dollars to thousands of dollars. So if you'r looking to make only a cup or so a week or bring out your Espresso Machines at a dinner party I recommend you purchase an inexpensive model. You will also need accessories as well such as grinder, roaster, coffee and cups.
Restaurants need a more expensive versions of Espresso Machines for their high demand of coffee from their customers. Barista's will make hundreds of Cappuccino's an hour and need a machine that will handle the demand. For example you may only need a 1 group machine. The 1 group will make one cup at a time. For larger quantities quicker you may need as a restaurant would need is at least a 3 group machine that has the capability of brewing three cups at once.
I would also recommend you purchase from a company that backs it product, has a warranty set up and has parts that can be replaced as needed.
There is nothing better than a fresh brewed cappuccino or espresso so why not get it right from your house! As always, do your homework first and you will not be disappointed.