To add to the very good reply above, Hitler basically lived as a tramp after leaving home (around the age 16). He lived in Vienna and he lived in a very infamous men's hostel (now closed) in the very run down Westbahnhof area of Vienna. Hitler lived off his inheritance which wasn't that much to begin with (Hitler lost both of his parents at a young age).

He was known as an eccentric, but as a very bookish eccentric. It is heavily considered that Hitler based his anti-Semitic philosophy on the gutter literature which he would have found at the time in Vienna.

Any calls from the military he was easily able to brush them off, since the Austrian military didn't want any tramps/vagrants in its army.

With his funds running out and tired of being an useless tramp/deadbeat, Hitler then moved to Munich. In Munich, he started his own business selling hand-painted postcards to tourists in the Munich city centre. If WWI had not broken out in 1914, he would have stayed a complete nobody, selling worthless and badly done hand-painted postcards to tourists.

However, August 1914 the war broke out and with it the massive hysteria of going to war. Hitler was caught up in this hysteria and joined the local Bavarian regiment in Munich. Compared to his former deadbeat life, Hitler was in the German Army for four years, even winning medals for bravery.

Recommended reading on this topic would be Joachim Fest's biography of Hitler.