Truth be told, the adjective poor was quite apt to describe Desmond, especially compared to other hunters in the guild. There were several reasons, and the fact that he had been with the association for less than a year was one of them.
Desmond also used most of his earnings to get resources for the girls back home; there wasn't much left after that. To add insult to injury, Desmond lost his beloved armor and a couple of accessories on his last mission. With the number of strange acid-spitting creatures he encountered back then, it was already a miracle Desmond didn't lose a leg or two over it.
The main reason why Desmond even came to the world of Veritas was strongly related to the huge payment for the mission he was given and the abundance of resources there. In other words, Desmond came to plunder everything in his path in order to put himself out of his misery.