To earn a little extra cash, buy medicine when it is less than one dollar and sell it to places that it is more expensive. Medicine is very light so you can carry a lot at once, and it helps your guys stay alive also.
Here's some badge ideas for this game:
"Leave me alone annoying robbers badge"-easy-5 pts-defeat a group of robbers
"The Richest Caravaneer ever badge"-hard-30 pts-earn $3,000,000
"I have no uncle badge"-impossible-60 pts-conquer Qubba without taking your uncle's inheritance (it is possible)
 "Caravaneer"){kind=icon}
 "Zombie Minesweeper"){kind=icon}
 "The Final Death Wish"){kind=icon}