I suggest you go to the marketplace and find out what leathers or cloth sell well. Then go and kill those types of beasties for a while. The most contested stuff isnt worth it though. You might wanna kill some boars or raptors or similar, since they have a good number of them in the world. About an hours worth of killing will net you 50k ish if you go with those types of skins. At the same time youre spiritbinding your stuff. When its bound convert it and get a new piece, then sell the materia, untill you are solvent again.
edit: the 50 k was based on my own hour of raptor killing, since both leathers, sinews sell well as hq and nq. This was on a bard. I cant say what the average kill rate would be for a non ae class.