I've visited 125 countries on a $15 a day budget - AMA!
My short bio: Hello and greetings from Almaty, Kazakhstan. I'm sitting here waiting for a couple of visas and thought I can use the time at least somewhat productive. ;)
I'm a German cyclist and traveller who has spend the last 8 years going around the world, starting at the age of 19. I'm an avid redditor and post on Imgur too, which all started from my game programming (I do a Dwarf Fortress mod as a hobby).
I really like to help other people start travelling, maybe answering questions here will do that. Otherwise you can often find me on r/bicycletouring or posting advice-related stuff on Imgur.
So far I've covered N-America, S-America, Europe and Australia/NewZealand. Been to all countries on these continents. Africa and Asia I have about half-way done, after that there are only island states left.(black:visited. dark-gray:current position) Hopefully I get to all the countries one day. :)
I usually ride a bike and had many bikes over the years. Atm I ride a full-suspension MTB with ultralight gear through the silk road.
I did spend around $45k so far, which comes down to ~$5625 a year or ~$15.4 per day. I do have a passive income, I rent out a house in Germany, combined with some savings.
Info on past tours: http://worldbicyclist.com/
Info on current tour: Facebook.
Lets hope for some interesting questions. :)
EDIT: Ok guys, that's it. 14h non-stop, answered ~1500 comments. Didn't sleep tonight. Hope the answered helped a few people. :)