The truth of course is that a witch will adopt her own way of casting and may happily contravene established correspondences to suit her own interpretations and beliefs. So although I can (and will in a minute) tell you what would be popularly considered the best phase of the moon to conduct a wealth spell, this isn't cast in stone. If your instinct urges you to cast at a different time - go with it.
Incidentally, I would never personally advocate delaying urgent magic to a different moon phase - if a spell needs doing as a matter of priority then little would be achieved by waiting for the moon to change before casting.
The best moon phase to complete a wealth spell would be the waxing moon. This is a period connected with change and growth .It is a time associated with actualising ideas and setting new projects in motion. Wealth spells can be aligned with the transition of the moon, to grow in strength until fruition at the peak of the full
Contrarily, spells involved with the decreasing of obstacles that prevent wealth would be better cast at the waning moon. This period, commonly associated with banishing can be utilised for the elimination and reduction of debts. Just as the growth of wealth can be linked to the waning moon,, the reduction of debt can be employed in spell work linked to the waning moon.
But as I say, it is all a matter of choice and perspective.