$500.00 you can do seasonal business.
the game day,  you can sell hats, t-shirt, water.
the concert day , you can sell Jewelry, pipe you name it
Friday night after bar, you can sell burrito,water
monday morning, you can sell breakfast burrito at office.
if you know oil change for auto mobile, you can do it door service. become handyman
weekend go to flee market and buy things you can sell it in craiglist.
you can make nice sign and get more business.
remember, visit nepal 2011 is coming....
you can advertisement for package tour (consultant with travel agent in Nepal) not a hard things right? and sale package and get commission
everything is possible, just make it happen.